Potential of bacterial derived biopesticides in pest management

Crop Protection 77 (2015) 52e64

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Crop Protection journal homepage: www.elsevier.com/locate/cropro

Review

Potential of bacterial derived biopesticides in pest management
s Mnif a, b, *, Dhouha Ghribi a, b Ine a b

Higher Institute of Biotechnology, Tunisia Unit Enzymes and Bioconversion, National School of Engineers, Tunisia

a r t i c l e i n f o

a b s t r a c t

Article history: Received 16 February 2015 Received in revised form 12 July 2015 Accepted 19 July 2015 Available online xxx

Biopesticides, key components of integrated pest management programs, are receiving practical attention as a means to reduce the amount of synthetic chemical products being used to control plant pests and diseases and to protect stored products. A large number of bacterial derived products have been released, several of which have already played dominant roles in the market. Bacterial pesticides are used to control pests, pathogens and weeds by a variety of mechanisms. Among them, they might act as competitors or inducers of host resistance in plant. Some act by inhibiting growth, feeding, development or reproduction of a pest or pathogen. The aim of this review is to provide an overview of the use of bacterial derived biopesticides for pest management and to discuss the current development and application of their various types. Detailed classification of Bacillus thuringiensis, Bacillus subtilis and Bacillus sphaericus based biopesticide is provided along with their insecticidal, mosquitocidal, nematicidal and antimicrobial activities. The review revealed great potential for further exploitation of bacterial derived biopesticides in plant protection. Pseudomonas sp. derived biopesticides and their potential use as mosquitocide, nematicide, antimicrobial agents and inducer of systemic resistance in plants are also discussed. © 2015 Elsevier Ltd. All rights reserved.

Keywords: Biopesticides Bacillus sp. Pseudomonas sp. Antifungal activity Larvicidal potency Nematicidal activity Plant protection

1. Introduction Agriculture has been facing the destructive activities of numerous pests including fungi, weeds and insects from time immemorial, sometimes leading to drastic decreases in yields and quantities. Pests are continuously being introduced to new areas either naturally or accidentally, or, in some cases, organisms that are intentionally introduced become pests. Global trade has resulted in increased numbers of aggressive non-native pest species being introduced to new areas. Controlling these aggressive species presents a serious challenge worldwide. Over years, chemical pesticides had made a great contribution to the battle against pests and diseases. However, their use resulted in the development of insecticide resistance, use-cancellation or deregistration of some insecticides due to human health and environmental concerns, extensive damage to the environment, pest resurgence, pest resistance to insecticides and lethal effects on nontarget organisms (Abudulai et al., 2001). Therefore, an eco-friendly alternative is required to generate higher quality and greater

 « Enzyme et Bioconversion », ENIS, BP W 3038 * Corresponding author. Unite Sfax, Tunisia. E-mail address: [email protected] (I. Mnif). http://dx.doi.org/10.1016/j.cropro.2015.07.017 0261-2194/© 2015 Elsevier Ltd. All rights reserved.

quantity of agricultural products. Hence, an urgent need has arise for the development of biopesticides for effective control of agricultural pests without causing serious harm to the ecological chain or worsening environmental pollution. We define a biopesticide as a mass-produced agent manufactured from a living microorganism or a natural product and sold for the control of plant pests (Organisation for Economic Co-operation and Development, 2009). Biopesticides fall into three different types according to the active substance: (i) micro-organisms; (ii) biochemicals; and (iii) semiochemicals (Chandler et al., 2011). Based on the natural resources from which they are derived, biopesticides are classified as microbial pesticides, botanical pesticides, zooid pesticides and genetically modified plants (Chandler et al., 2011). They were swiftly becoming the preferred choice for pest control thanks to the great increase of the number of areas in which they were used moving from one year to another. Biopesticides were usually applied to control rather than to destroy pests. They were also more selective than chemical pesticides. In fact, most biopesticides had the advantage of higher selectivity and non-target biological safety (Cheng et al., 2010). The biopesticides characteristics included lowresidue and high-performance, fewer toxic side effects and good compatibility with the environment. The resistance to biopesticides in target organisms was not easily generated, unlike in many cases of their chemical counterparts. They are fast becoming a new trend

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in the global pesticide industry. Microbial biopesticides derived from bacteria, fungi, oomycetes, viruses and protozoa are all being widely used for the biological control of pestiferous insects, plant pathogens and weeds. For all crop types, bacterial biopesticides claim about 74% of the market; fungal biopesticides, about 10%; viral biopesticides, 5%; predator biopesticides, 8%; and “other” biopesticides, 3% (Thakore, 2006). However, only a few insect pathogenic bacteria have been developed as biocontrol agents. The most commonly used microbial biopesticide is the entomopathogenic bacterium Bacillus thuringiensis (Bt) (Berliner), which produces a crystal protein (d-endotoxin) during bacterial sporulation that is capable of causing lysis of gut cells when consumed by susceptible insects (Jisha et al., 2013). Bacillus subtilis (Ehrenberg), Pseudomonas fluorescens (Trevisan) and P. aureofaciens (Kluyver) are being applied against a variety of plant pathogens including, especially, damping-off and soft rots (Berg, 2009). In this review, we will discuss a large variety of bacterial derived biopesticides including those derived from Gram positive isolates; B. thuringiensis, B. subtilis, Bacillus sphaericus and Bacillus sp. based biopesticides and those derived from Gram negative isolates Pseudomonas sp. 2. Bacillus thuringiensis based biopesticide The entomopathogenic organism, B. thuringiensis is a grampositive spore-forming bacterium that produces crystalline proteins called d-endotoxins released to the environment after lysis of the cell wall at the end of sporulation (Jisha et al., 2013). The dendotoxin is host specific and can cause death within 48 h (Jisha et al., 2013). It does not harm vertebrates and is safe to the peoples and the environment (Van Driesche et al., 2008). B. thuringiensis sprays are an emergent policy for pest management on fruit and vegetable crops where their high level of selectivity and safety are considered desirable, and where resistance to synthetic chemical insecticides is a problem (Van Driesche et al., 2008). Owing a wide spectrum of bioactivity, B. thuringiensis based biopesticide presented approximately 95% of microorganisms used for pest control. Table 1 presents a wide array of B. thuringiensis based biopesticides along with their nature and the antagonist strain. As suggested by Schünemann et al. (2014), there are different commercial B. thuringiensis products developed for control of agricultural insect pests and also against mosquito species. Most of the spore-crystal formulations are obtained from different strains including B. thuringiensis var. kurstaki (Btk)-isolate HD1 (contains Cry1Aa, Cry1Ab, Cry1Ac, and Cry2Aa proteins); B. thuringiensis var. kurstaki (Btk)-isolate HD73 (contains Cry1Ac); B. thuringiensis var. aizawai-isolate HD137 (contains Cry1Aa, Cry1B, Cry1Ca, and Cry1Da); B. thuringiensis var. San Diego and B. thuringiensis var. tenebrionis (contains Cry3Aa) and B. thuringiensis var. israelensis (contains Cry4A, Cry4B, Cry11A, and Cyt1Aa) toxins (Schünemann et al., 2014). In a study conducted by Raddadi et al. (2009), 16 B. thuringiensis strains were investigated for their polyvalent biocontrol potential mediated by a screening of their capacity to protect plants against phytopathogenic insects, fungi and bacteria. They have shown that two strains B. thuringiensis subsp. entomocidus HD9 and B. thuringiensis subsp. tochigiensis HD868 have several activities among them chitinolytic activity, fungal inhibition, b-1,3-glucanase and autolysin and bacteriocin activities suggesting their potential feasibility as biological control agents (Raddadi et al., 2009). 2.1. Insecticidal activity of B. thuringiensis derived biopesticides The mode of action of B. thuringiensis proteins involves

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numerous events which would be achieved several hours after ingestion leading to insect death. After ingestion, the crystals are solubilized by the alkaline conditions in the insect midgut and are, afterwards, proteolytically transformed into a toxic core fragment (Jisha et al., 2013). During proteolytic activation, peptides from the N terminus and C terminus are cleaved from the full protein. Activated toxin binds to receptors located on the apical microvillus membranes of epithelial midgut cells. After binding, toxin changes conformation, allowing its insertion into the cell membrane. Subsequently, oligomerization occurs, and this oligomer forms a pore or ion channel within the functional receptors contained on the brush borders membranes, causing disruption of membrane transport and cell lysis and leading to insect death (Jisha et al., 2013; Schünemann et al., 2014). B. thuringiensis derived biopesticide can act either on Lepidoptera, Dipterans and Coleopterans insects. Lepidoptera encompasses the majority of susceptible species belonging to agriculturally important families such as Cossidae, Gelechiidae, Lymantriidae, Noctuidae, Pieridae, Pyralidae, Thaumetopoetidae, Tortricidae and Yponomeutidae (Gathmann and Priesnitz, 2014). Dipterans are also important target pests and many of them are highly susceptible to B. thuringiensis. This order includes the families Tephritidae, Culicidae, Muscidae, Simuliidae and Tipulidae (Lysyk, 2006). Coleopterans are important pests in agriculture and forestry. Several families such as Chrysomelidae, Curculionidae, Tenebrionidae and Scarabeidae have recently been found to be susceptible to toxic activity of the crystals (Gathmann and Priesnitz, 2014). Zhong et al. (2000) characterized a B. thuringiensis delta-endotoxin which is toxic to the three orders of insects (Diptera, Coleoptera and Lepidoptera). It's well documented that the encoded products of cry genes of certain B. thuringiensis are toxic against diverse insect order such as Hymenoptera, Hemiptera, Orthptera, Acaria and Phthiraptera (Mallophaga) (Eswarapriya et al., 2010). Wu et al. (2011) described the toxic effect of a novel B. thuringiensis d-endotoxin against Locusts (Orthoptera: Acrididae): Locusta migratoria manilensis; pests that cause extensive destruction of crops. Also, previous studies reported the entomocidal activity of novel B. thuringiensis-endotoxins to Lygus Hesperus Knight (Hemiptera: Miridae) (Wellman^ te , 2005), the cotton aphids Aphis gossypii (HemiDesbiens and Co ptera: Aphididae) and whiteflies Bemisia tabaci (Hemiptera: Aleyrodidae) (Malik and Riazuddin, 2006). Craveiro et al. (2010) reported the efficient biological control of sugarcane giant borer caused by the Lepidopteran larvae Telchin licus licus (Castniidae) by variants of Cry1Ia toxins. Other studies reported the high toxicity of B. thuringiensis Cry protein towards Anthonomus grandis Boheman (Coleoptera: Curculionidae) (de Souza Aguiar et al., 2012) and towards Cylas puncticollis and Cylas brunneus (Coleoptera: Brentidae) (Ekobu et al., 2010). Another interesting protein derived from a B. thuringiensis strain is the Vegetative Insecticidal Proteins (Vip) (Yu et al., 2011). It includes the binary toxin Vip1 and Vip2 with Coleopteran specificity and Vip3 with a wide activity spectrum against Lepidoptera (Yu et al., 2011). Shingote et al. (2013) reported the insecticidal potency of derived Vip1/Vip2 against the Coleopteran store grain pest, Sitophilus zeamais (Curculionidae family) with 60% mortality. As presented by Fang et al. (2007), Vip3Ac1 showed high insecticidal activity against the Lepidoptera larvae, the fall armyworm Spodoptera frugiperda (Noctuidae) and the cotton bollworm Helicoverpa zea (Noctuidae) but very low activity against the silk worm Bombyx mori (Bombycidae). Moreover, Beard et al. (2008) reported the insecticidal activity of B. thuringiensis Vip 3Bb2 towards the cotton bollworm Helicoverpa armigera (Noctuidae). Similarly, Schünemann et al. (2014) reported the effectiveness of B. thuringiensis toxins in the control of velvetbean Caterpillar;

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Table 1 Bacillus thuringiensis based biopesticide. Bioactive compound

Producing strain

Insecticidal activity Toxins, Cry protein and Vip Cry toxins B. thuringiensis

Antagonist strain

References

Eswarapriya et al., 2010 Wu et al., 2011 Schünemann et al., 2014 Craveiro et al., 2010 Lysyk et al., 2010 Wellman-Desbiens ^ te  2005 and Co Malik and Riazuddin 2006 Donovan et al., 2006 Liu et al., 2014

d-Endotoxin Toxins

B. thuringiensis B. thuringiensis

Diverse insect order such as Hymenoptera, Hemiptera, Orthptera, Acaria and Phthiraptera (Mallophaga) Locusta migratoria manilensis Anticarsia gemmatalis and Nezara viridula

Cry1Ia toxins Endotoxins

B. thuringiensis B. thuringiensis B. thuringiensis

Telchin licus licus (Castniidae) immature horn fly and stable fly (Diptera: Muscidae) Lygus Hesperus

Endotoxins

B. thuringiensis

Aphis gossypii and Bemisia tabaci

Sip1A Thuringiensin (Thu) (bexotoxin) Cry protein

B. thuringiensis B. thuringiensis

Diabrotica undecimpunctata howardi and Diabrotica virgifera virgifera Diptera, Coleoptera, Lepidoptera, Hymenoptera, Orthoptera, and Isoptera

B. thuringiensis

Anthonomus grandis

Cry protein Vip1/Vip2 Vip3Ac1 Vip 3Bb2 Mycolytic enzymes Exochitinase

B. B. B. B.

Cylas puncticollis and Cylas brunneus Sitophilus zeamais Spodoptera frugiperda, Helicoverpa zea and Bombyx mori Helicoverpa armigera

de Souza Aguiar et al., 2012 Ekobu et al., 2010 Shingote et al., 2013 Fang et al., 2007 Beard et al., 2008

Spodoptera exigua and Helicoverpa armigera

Vega et al., 2006

Spodoptera exigua and Helicoverpa armigera

Liu et al., 2009

Diprion similis, Acantholyda erythrocephala, Pikonema alaskensis, Neodiprion sertifer and Choristoneura fumiferana

van Frankenhuyzen and Tonon 2013

Pieris rapae crucivora

Kim et al., 2004

Meloidogyne incognita Meloidogyne incognita

Mohammed et al., 2008 Peng et al., 2011

Erwinia carotovora

Dong et al., 2004

Phytophthora and Fusarium Oomycetes and their relatives

Kamenek et al., 2012 Zhou et al., 2008

Agrobacterium tumefaciens

Kamoun et al., 2011

P. syringae, P. savastanoi and Paucimonas lemoignei

Serpil et al., 2013

Peanibacillus

Cherif et al., 2008

Sclerotium rolfsii, Aspergillus terreus, A. flavus, Nigrospora sp, Rhizopus sp, A. niger, Fusarium sp, A. candidus, Absidia sp., Helminthosporium sp., Curvularia sp. and A. fumigatus Rhizoctonia solani, Physalospora piricola, Penicillium chrysogenum and Botrytis cinerea

Reyes-Ramirez et al., 2004 Vega et al., 2006

Inhibits sporangia germination of fungi

Liu et al., 2009

Stachybotrys charatum Colletotrichum gloeosporioides

Hathout et al., 2000 Kim et al., 2004

thuringiensis thuringiensis thuringiensis thuringiensis

B. thuringiensis subsp. aizawaiandits Chitinase B. thuringiensis subsp. colmeri Crystalespore suspension B. thuringiensis PS201T6 Biosurfactant Lipopeptide B. thuringiensis Nematicidal activity Toxins B. thuringiensis Cry6Aa and Cry55Aa B. thuringiensis toxins Antimicrobial activity Secondary bioactive metabolites Acyl-homoserine lactone- B. thuringiensis lactonase Delta-endotoxin B. thuringiensis B. thuringiensis Linear aminopolyol antibiotic, zwittermicin A Bacteriocins: Bacthuricin B. thuringiensis F103 Thuricin Bn1 B. thuringiensis subsp. kurstaki Entomocin 110 B. thuringiensis subsp. entomocidus Mycolytic enzymes Exochitinase B. thuringiensis var israelensis Exochitinase B. thuringiensis subsp. aizawaiandits Chitinase B. thuringiensis subsp. colmeri 15A3 Biosurfactant Kurstakins B. thuringiensis Fengycin like lipopeptide B. thuringiensis CMB26

Anticarsia gemmatalis (Lepidoptera: Noctuidae) and the green stink bug; Nezara viridula (Hemiptera: Pentatomidae) in soybean culture. Although the Cry proteins and d-endotoxin having larvicidal activities, chitinase enzymes can be involved in the insecticidal potency of B. thuringiensis against certain larvae as all insects have a chitin layer covering their bodies, which is susceptible to degradation by these enzymes (Singh et al., 2014). In this aim, Vega et al. (2006) purified and characterized a novel exochitinase from B. thuringiensis subsp. aizawaiandits presenting a lethal effect on

Spodoptera exigua and H. armigera larvae (Lepidoptera: Noctuidae). Similarly, chitinase from B. thuringiensis subsp. colmeri could reduce the LC50 (50% lethal concentration) of B. thuringiensis derived crystal protein against S. exigua and H. armigera larvae by approximately 26% and 30% (Liu et al., 2009). Donovan et al. (2006) reported the discovery of a novel protein from B. thuringiensis, Sip1A with insecticidal activity against southern corn rootworm larvae; Diabrotica undecimpunctata howardi (Coleoptera: Chrysomelidae) and western corn rootworm

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larvae; Diabrotica virgifera virgifera (Coleopteran: Chrysomelidae). Thuringiensin (Thu), also known as b-exotoxin, a thermostable secondary metabolite secreted by B. thuringiensis with oligosaccharide nature, has insecticidal activity against a wide range of insects, including species belonging to the orders Diptera, Coleoptera, Lepidoptera, Hymenoptera, Orthoptera and Isoptera and several nematode species (Liu et al., 2014). Moreover, van Frankenhuyzen and Tonon (2013) reported the toxicity of a crystalespore suspension of B. thuringiensis PS201T6 towards Hymenoptera insect larvae Diprion similis (Diprionidae) and Acantholyda erythrocephala (Pamphiliidae), Pikonema alaskensis (Tenthredinidae) and Neodiprion sertifer (Diprionidae), as well as the Lepidopteran spruce budworm; Choristoneura fumiferana (Tortricidae). Furthermore, B. thuringiensis derived lipopeptide exhibited insecticidal activity towards larvae of the cabbage white butterfly Pieris rapae crucivora (Lepidoptera: Pieridae) with a potent membrane permeabilizing of the target larvae (Kim et al., 2004). 2.2. Nematicidal activity of B. thuringiensis derived biopesticides Root-knot nematodes are a growing concern for vegetable producers, because chemical nematicides are gradually disappearing. In addition to the toxic activities to insects, some novel strains of B. thuringiensis produce crystals with activity against nematodes, protozoans, flukes, collembolans, mites and worms (Rosas-García, 2009; Jisha et al., 2013). In deed, some nematodes such as Haemonchus (Strongylida: Trichostrongylidae) and Nematodirus (Strongylida: Molineidae), soil nematodes and vegetable parasites can be controlled through the use of B. thuringiensis toxins (Li et al., 2007). Two strains of B. thuringiensis were identified with significant activity in inhibiting larval development of the nematode parasites of livestock Haemonchus contortus (Strongylida: Trichostrongylidae), Trichostrongylus columbiformes (Rhabditida: Trichostrongylidae) and Ostertagia circumcincta (Strongylida: Trichostrongylidae) (Kotze et al., 2005). Mohammed et al. (2008) described the biocontrol efficiency of B. thuringiensis toxins against the root-knot nematode, Meloidogyne incognita (Tylenchida: Heteroderidae). Peng et al. (2011) reported the synergistic activity between B. thuringiensis Cry6Aa and Cry55Aa toxins against M. incognita (Tylenchida: Heteroderidae). Li et al. (2008) proved that expression of Cry5B protein from B. thuringiensis in plant roots confers resistance to root-knot nematode. As suggested by Wei et al. (2003), toxicity of B. thuringiensis crystal protein in nematodes correlates with damage to the intestine, consistent with the mechanism of crystal toxin action in insects. 2.3. Antimicrobial activity of B. thuringiensis derived biopesticides: implication in plant protection In addition to insecticidal and mosquito activities, d-endotoxins from B. thuringiensis exhibited antibacterial and antifungal activities suggesting their possible implication in plant protection. In a study conducted by Lucon et al. (2010), treatment of the infested citrus fruit by B. thuringiensis isolates significantly reduced the mycelial growth of Guignardia citricarpa phyto-pathogen. In planta, B. thuringiensis significantly decreased the incidence of Erwinia carotovora infection and symptom development of potato soft rot caused by the pathogen probably correlated to the ability of bacterial strains to produce acyl-homoserine lactone-lactonase (Dong et al., 2004). As suggested by Kamenek et al. (2012), B. thuringiensis d-endotoxin exhibited an antifungal activity against phytopathogenic fungi related to Phytophthora and Fusarium. A notable protective effect of the endotoxin against Fusarium oxysporum f. sp. lycopersici, a causative agent of wilt and late blight

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disease, was estimated throughout the storage of tomatoes. Zhou et al. (2008) reported that acyl homoserine lactone lactonase produced by B. thuringiensis can be implicated in quenching bacterial quorum sensing system that in turn silences bacterial virulence permitting therefore development of a new strategy against plant bacterial diseases. Moreover, they reported the discovery of a linear aminopolyol antibiotic, zwittermicin A, with higher activity against oomycetes and their relatives, as well as some gram-negative bacteria promoting their use in plant disease biocontrol (Zhou et al., 2008). As all fungi have a chitin layer covering their bodies, chitinase enzymes may play an important role in the biological control of plant phytopathogenic fungi. An exochitinase derived from B. thuringiensis var israelensis exhibited a fungal inhibition of about 100% for Sclerotium rolfsii; 55%e82% for Aspergillus terreus, Aspergillus flavus, Nigrospora sp, Rhizopus sp, A. niger, Fusarium sp, A. candidus, Absidia sp. and Helminthosporium sp; 45% for Curvularia sp. and 10% for A. fumigatus (P < 0.05) (Reyes-Ramirez et al., 2004). Also, it increased the in vivo germination of infected soybean seeds with S. rolfsii to 90% (Reyes-Ramirez et al., 2004). Vega et al. (2006) purified and characterized a novel exochitinase from B. thuringiensis subsp. aizawaiandits inhibiting the spore germination of four species of fungi; Rhizoctonia solani, Physalospora piricola, Penicillium chrysogenum and Botrytis cinerea. Similarly, chitinase from B. thuringiensis subsp. colmeri 15A3 inhibited sporangia germination of fungi with an IC50 value (50% inhibited concentration) of about 4 mg/ml (Liu et al., 2009). Furthermore, over the past seven years there has been a marked interest in identifying and characterizing bacteriocins as potential biopesticides involved in plant protection against phytopathogenic bacteria. They are ribosomally synthesized antimicrobial compounds produced by the spore-forming bacterium B. thuringiensis. For example, Bacthuricin F103 is able to inhibit Agrobacterium tumefaciens that causes crown gall disease in tomato and vineyard crops (Kamoun et al., 2011). It has also been demonstrated that Thuricin Bn1 derived from B. thuringiensis subsp. kurstaki elaborates inhibitory effects on other phytopathogens, including Pseudomonas syringae, P. savastanoi and Paucimonas lemoignei (Serpil et al., 2013). Moreover, B. thuringiensis subsp. entomocidus derived Entomocin 110 was active against Peanibacillus, an endosporeforming bacterium; the etiologic agent of foulbrood disease; that attacks honeybee larvae (Apis mellifera) and other Apis spp. (Pollinators insect) (Cherif et al., 2008). Moreover, B. thuringiensis derived lipopeptides are recognized by their antifungal activities and are implicated in the biocontrol of plant phytopathogenic fungi. Kurstakins; a new class of lipopeptides isolated from B. thuringiensis; inhibited the growth of Stachybotrys charatum fungus (Hathout et al., 2000). Similarly, a fengycin like lipopeptide derived from B. thuringiensis CMB26 strain; exhibited fungicidal activity against the phytopathogenic fungus Colletotrichum gloeosporioides (Kim et al., 2004). Studies revealed the cell surface shrinking of treated fungus by the lipopeptide suggesting its lethal effect by acting on the cell surface by the potent permeabilizing activity (Kim et al., 2004).

3. Bacillus subtilis based biopesticide B. subtilis, an ubiquitous bacterium commonly found in various ecological niches that does not have any history of pathogenicity from contact in the environment, was shown to be a potential biocontrol agent of harmful phyto-pathogenic fungi and bacteria, mosquitoes and nematodes (Ongena et al., 2010). Table 2 enumerates a wide array of B. subtilis derived biopesticides along with their chemical nature, producing strain and antagonist strain.

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Table 2 Bacillus subtilis based biopesticides. Bioactive compound

Producing strain

Antagonist strain

References

Mosquitocidal activity of B. subtilis derived biopesticides Lipopeptide B. subtilis Drosophila melanogaster Lipopeptide B. subtilis Culex quinquefasciatus Lipopeptide B. subtilis Aedes aegypti Lipopeptide B. subtilis Anopheles stephensi Lipopeptide B. subtilis Prays oleae, Spodoptera littoralis, Ephestia kuehniella, Ectomyelois ceratoniae SPB1 Nematicidal activity of B. subtilis derived biopesticides Cells and spores of B. subtilis B. subtilis M. incognita, Heterodera cajani, Heterodera avenae and Anguina tritci e B. subtilis M. incognita, Pratylenchus coffeae, Radopholus similis and Helicotylenchus multicinctus e B. subtilis Aphelenchoides besseyi and Ditylenchus destructor Surfactin and iturin B. subtilis M. incognita Antimicrobial activity of B. subtilis derived biopesticides Biosurfactant Iturin A B. subtilis R. solani and Phomopsis RB14-C Surfactin B. subtilis Aspergillus flavus and Colletotrichum gloeosporioides Iturin A B. subtilis Pestalotiopsis eugeniae BS-99-H Lipopeptide B. subtilis Fusarium spp., Aspergillus spp., and Biopolaris sorokiniana Gageotetrins A
C B. subtilis Phytophthora capsici Mycolytic enzymes B. subtilis Fusarium Chitinase, b-1, 3-glucanase, siderophores and indole-3-acetic B579 acid Chitinase B. subtilis Rhizoctonia Protease, chitinase and b-1,3B. subtilis Aspergillus flavus glucanase BCC 6327 Chitinase, glucanase and cellulase B. subtilis Colletotrichum gloeosporioides OGC1 Bioactive metabolites Bacteriocin B. subtilis Agrobacterium tumefaciens 14B Protein E2 B. subtilis Fusarium graminearum, Macrophoma kuwatsukai, Rhizoctonia cerealis, Fusarium strain EDR4 oxysporum f.sp. vasinfectum, Botrytis cinerea and Gaeumannomyces graminis var. tritici Bacteriocin B. subtilis Alternaria solani IH7

3.1. Mosquitocidal activity of B. subtilis derived biopesticides Previous studies reported the mosquito larvicidal potency of B. subtilis derived metabolites. Effective formulations consisting of B. subtilis lipopeptide biosurfactant were used for control of Drosophila melanogaster (Diptera: Drosophilidae) (Assie et al., 2002), Culex quinquefasciatus (Diptera: Culicidae) (Das and Mukherjee, 2006), Anopheles stephensi (Diptera: Culicidae) (Manonmani et al., 2011) and Aedes aegypti (Diptera: Culicidae) (Geetha et al., 2010). As suggested by Geetha and Manonmani (2008), the pupal stages of A. stephensi, C. quinquefasciatus and A. aegypti [LC50 (mg/ml) 2, 7.3 and 11.8 respectively] were found to be more susceptible to the lipopeptide crude mosquitocidal toxin than larval stages [LC50 (mg/ml) 19, 23 and 34 respectively] with A. stephensi being the most susceptible species. Recently, a lipopeptide biosurfactant derived from B. subtilis SPB1 was demonstrated as an efficient biocontrol agent against the olive moth Prays oleae (Lepidoptera: Yponomeutidae) with an LC50 value of 142 mg/ml (Ghribi et al., 2011), the Egyptian cotton leaf worm Spodoptera littoralis (Lepidoptera: Noctuidae) with an LC50 value of 251 ng/cm2 (Ghribi et al., 2012a), the third instar larvae Ephestia kuehniella (Lepidoptera: Pyralidae) with an LC50 value of 257 mg/g (Ghribi et al., 2012b) and the carob moth Ectomyelois ceratoniae (Lepidoptera: Pyralidae) with an LC50 value of 152 mg/g (Mnif et al., 2013). The histopathological changes occurred in the larval midgut of the treated S. littoralis with B. subtilis SPB1 biosurfactant were vacuolization and necrosis of the epithelial cells visualized by a destruction of the cells and their boundaries (Ghribi

Assie et al., 2002 Das and Mukherjee 2006 Geetha et al., 2010 Manonmani et al., 2011 Ghribi et al., 2011; Ghribi et al., 2012a; 2012b; Mnif et al., 2013 Gokte and Swarup 1988 Jonathan and Umamaheswari 2006 Xia et al., 2011 Kavitha et al., 2012

Kita et al., 2005 Mohammadipour et al., 2009 Lin et al., 2010 Velho et al., 2011 Tareq et al., 2014 Chen et al., 2010

Yan et al., 2011 Thakaew and Niamsup 2013 Ashwini and Srividya 2014 Hammami et al., 2009 Liu et al., 2010 Hammami et al., 2011

et al., 2012a). These suggest that this lipopeptide is capable of causing death of an insect when entering into tissues in adequate amounts. Moreover, non-killed larvae treated with SPB1 biosurfactant were blocked at their first instar stage and the percentage of larvae that survived and succeeded to pupate increased by decreasing the concentration (Ghribi et al., 2012a). Brush border membrane vesicles prepared from insect midgets have proven to be an important tool to study toxin receptors (Ruiz et al., 2004; Abdelkefi-Mesrati et al., 2011). Ligant blot analyzes and homologous competition experiments showed that the SPB1 biosurfactant specifically bound to a putative receptor of 45 kDa in S. littoralis midgut (Ghribi et al., 2012b). 3.2. Nematicidal activity of B. subtilis derived biopesticides Regarding literature reviews, it was showed that cells and spores of B. subtilis were toxic to nematodes M. incognita (Tylenchida: Heteroderidae), Heterodera cajani (Tylenchida: Heteroderidae), Heterodera avenae (Tylenchida: Heteroderidae) and Anguina tritci (Tylenchida: Tylenchidae) (Gokte and Swarup, 1988). Recently, nematicidal activity of B. subtilis isolates was reported by Xia et al. (2011) against Aphelenchoides besseyi (Tylenchida: Aphelenchoididae) and Ditylenchus destructor (Tylenchida: Anguinidae). In a study conducted by Jonathan and Umamaheswari (2006), the endophytic bacterial isolates B. subtilis was active against the nematodes of banana viz., root-knot nematode M. incognita (Tylenchida: Heteroderidae); lesion nematode Pratylenchus coffeae (Tylenchida: Hoplolaimidae); burrowing nematode Radopholus

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similis (Tylenchida: Hoplolaimidae) and spiral nematode Helicotylenchus multicinctus (Tylenchida: Hoplolaimidae). A reduction in nematode population along with a significant increase in shoot height and weight, root length and weight, pseudostem girth and number of leaves coupled with an enhancement of enzymes responsible for induction of systemic resistance such as peroxidase, polyphenol oxidase and phenylalanine ammonia lyase were also observed (Jonathan and Umamaheswari, 2006). As presented by Kavitha et al. (2012), endophytic B. subtilis strains with high surfactin and iturin activity, suppressed hatching of eggs and killed second stage juveniles of the M. incognita nematode (Tylenchida: Heteroderidae); one of the most damaging pathogens, attacking a wide range of crops; under in vitro conditions. 3.3. Antimicrobial activity of B. subtilis derived biopesticides: implication in plant protection B. subtilis derived lipopeptides have been reported for their biological control potential against several plant pests. In this aim, it is well documented that lipopeptides, the prevailing group of biosurfactant compounds are among the most popular and powerful metabolites in combating and treating fungal diseases infection in vitro and in vivo (Ongena and Jacques, 2007). Mohammadipour et al. (2009) described the in vitro antifungal activity of surfactin molecules towards fungal pathogens A. flavus and Colletotrichum gloeosporioides. A B. subtilis derived lipopeptide exhibited growth inhibition of phytopathogenic fungi like Fusarium spp., Aspergillus spp. and Biopolaris sorokiniana enabling their use as biocontrol agent (Velho et al., 2011). Kita et al. (2005) discussed the suppressive ability of iturin A produced by B. subtilis RB14-C against the damping-off of tomato seedlings caused by R. solani and Phomopsis root rot of cucumber. A novel bioactive linear lipopeptide compounds produced by a marine B. subtilis; gageotetrins AeC; displayed good time course motility inhibition and lytic activity against the late blight pathogen Phytophthora capsici; which causes enormous economic damage in cucumber, pepper, tomato and beans; at 0.02 mM (Tareq et al., 2014). As suggested by Chitarra et al. (2003), an iturin-like compounds produced by B. subtilis YM 10e20 may permeabilize fungal spores and inhibit their germination. Antifungal activity of B. subtilis isolates can be mediated by the pore forming and permeabilizing activities of the lipopeptides compounds. Swelling and deformation of fungus hyphae of Pestalotiopsis eugeniae was assessed after treatment by the Iturin A of B. subtilis BS-99-H (Lin et al., 2010). Several B. subtilis strains produced mycolytic enzymes involved in the biocontrol of plant rot disease through the lysis of cell walls of pathogenic fungi. As suggested by Yan et al. (2011), B. subtilis produced a chitinase enzyme promoting the sprouting and seedling growth of tomato (the fresh and dry weight of tomato seedlings increased by 43% and 19% respectively) and inhibiting tomato Rhizoctonia rot with control efficacies of 21% and 35% in the greenhouse and field respectively. B. subtilis BCC 6327, involved in the biocontrol of Aflatoxigenic Fungi, produced protease, chitinase and b-1,3-glucanase enzymes possessing the ability to hydrolyze dried mycelia of A. flavus (Thakaew and Niamsup, 2013). As presented by Ashwini and Srividya (2014), chitinase, glucanase and cellulase activities produced by a soil bacterium B. subtilis were involved in the management of anthracnose disease of chilli caused by Colletotrichum gloeosporioides OGC1. As presented by Chen et al. (2010), a B. subtilis B579 strain exhibited a biocontrol activity of cucumber Fusarium wilt through the production of plant defense enzymes and phytohormone; chitinase, b-1, 3-glucanase, siderophores and indole-3-acetic acid; and phosphate solubilization. Other strains exhibited their biocontrol potency through the production of small protein molecules inhibiting fungi

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development. An antifungal protein E2; derived from the endophytic B. subtilis strain EDR4 of wheat; exhibited a high in vitro inhibitory activity on mycelium growth of Fusarium graminearum, Macrophoma kuwatsukai, Rhizoctonia cerealis, F. oxysporum f.sp. vasinfectum, B. cinerea and Gaeumannomyces graminis var. tritici (Ggt) with a potent inhibitory activity of take-all in wheat caused by G. graminis var. tritici in vivo (Liu et al., 2010). Hammami et al. (2009) reported the efficient biocontrol of Agrobacterium tumefaciens infections in plants visualized by a reduction of both the percentage of galled plants and the number of galls in tomato by B. subtilis 14B and its bacteriocin. Another bacteriocin purified from B. subtilis IH7 exhibited effective disinfectant properties against seedborne diseases and had a significant effects on the control of damping-off disease groups at the pre-germination stage, of root rot caused by Alternaria solani, as well as of wilt diseases and other bacterial seed-borne pathogens (Hammami et al., 2011). 4. Bacillus sphaericus based biopesticide: potential effect in the biocontrol of mosquito invasion B. sphaericus is an aerobic, rod-shaped, endospore forming gram positive soil bacterium. During sporulation, it produces parasporal crystal inclusion bodies including Cry48Aa-Cry49Aa binary toxin, Mtx1 and Mtx2 toxins and binary toxin BinA and BinB that are mosquito larva specific (Table 3). Upon ingestion, they cause mosquito larvae death in the same way as B. thuringiensis kurstaki is to Lepidoptera and Coleoptera. As suggested by Park et al. (2010), lethal strains of B. sphaericus produce one or two combinations of three different types of toxins. These are (1) the binary toxin (Bin) composed of two proteins of 42 kDa (BinA) and 51 kDa (BinB), which are synthesized during sporulation and co-crystallize, (2) the soluble mosquitocidal toxins (Mtx1, Mtx2 and Mtx3) produced during vegetative growth and (3) the two-component crystal toxin (Cry48Aa1/Cry49Aa1). Rungrod et al. (2009) reported the synergistic activity of Mtx1 and Mtx2 toxins against A. aegypti (Diptera: Culicidae) larvae. Jones et al. (2008) reported the highly restricted target specificity of the Cry48Aa-Cry49Aa binary toxin from B. sphaericus towards C. quinquefasciatus mosquito larvae (Diptera: Culicidae) with non-toxicity to Coleopteran, Lepidopteran and other Dipteran insects including closely related Aedes and Anopheles mosquitoes. Bin toxin can increase the toxicity of other mosquitocidal proteins and may be useful to increase the activity of commercial bacterial larvicides (Rahman et al., 2012). As discussed by Rahman et al. (2012), the larvicidal action of the entomopathogen B. sphaericus towards C. quinquefasciatus (Diptera: Culicidae) is due to the binary (Bin) toxin protein present in crystals which are produced during bacterial sporulation. Hire et al. (2009) reported the purification of a binary toxin from B. sphaericus ISPC-8 composed of toxic BinA (41.9 kDa) and receptor binding BinB (51.4 kDa) polypeptides active against vectors of filariasis, encephalitis and malaria. Hire et al. (2010) characterized highly toxic indigenous strains of B. sphaericus Dongre with a wide spectrum of mosquitocidal activities against C. quinquefasciatus, followed by Culex tritaeniorhynchus, Aedes albopictus and A. aegypti (Diptera: Culicidae). The mosquitocidal activity can be associated to the production of a binary toxin protein with an LC50 value of 6.32 ng/mL against C. quinquefasciatus larvae (Diptera: Culicidae) after 48 h of incubation (Hire et al., 2010). Rahman et al. (2012) studied the mode of action of the two proteins of 42 (BinA) and 51 (BinB) kDa, that are required for toxicity to mosquito larvae midgut. They are cleaved by proteases, yielding peptides of 39 kDa and 43 kDa, respectively that form the active toxin (Rahman et al., 2012). Their mode of action is similar to that of thuringiensis Berliner. Since they have to be ingested and

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Table 3 Other Bacillus sp. based biopesticides. Bioactive compound

Producing strain

Antagonist strain

References

B. sphaericus derived biopesticides Sphaericolysin

B. sphaericus

Cry48Aa-Cry49Aa binary toxin

B. sphaericus

The cockroaches Blattela germanica and the common cutworms Spodoptera litura Culex quinquefasciatus

Mtx1 and Mtx2 toxins

B. sphaericus

Aedes aegypti

Binary toxin BinA and BinB

B. sphaericus ISPC-8

Vectors of filariasis, encephalitis and malaria

Binary toxin protein

B. sphaericus Dongre

Binary (Bin) toxin protein

B. sphaericus

Culex quinquefasciatus, Culex tritaeniorhynchus, Aedes albopictus and Aedes aegypti Culex quinquefasciatus

Nishiwaki et al., 2007 Jones et al., 2008 Rungrod et al., 2009 Hire et al., 2009 Hire et al., 2010 Rahman et al., 2012

B. amyloliquefaciens derived biopesticides Chitinase

B. amyloliquefaciens

Micrococcus lysodeikticus

Protein

B. amyloliquefaciens

Colletotrichum lagenarium

Iturin or surfactin and fengycin

B. amyloliquefaciens

Sclerotinia

Biosurfactant

B. amyloliquefaciens

Volatile compounds

B. amyloliquefaciens

Anopheles stephensi, Culex quinquefasciatus and Aedes aegypti Fusarium oxysporum f. sp. cubense

B. licheniformis derived biopesticides e

B. licheniformis

Xanthomonas campestris

e

B. licheniformis

Botrytis mali

Other Bacillus derived biopesticides e

B. firmus

Amino acids

Paenibacillus macerans

Radopholus similis, Meloidogyne incognita and Ditylenchus dipsaci. M. exigua

e

Paenibacillus polymyxa and Paenibacillus lentimorbus B. vallismortis ZZ185

Bacillomycin D Benzeneacetaldehyde, 2-nonanone, decanal, 2undecanone and dimethyl disulphide Antibiotic

B. megaterium

Chitinase

B. cereus strain DFE4 and B. amyloliquefaciens strain DFE16 B. megaterium MB3, B. subtilis MB14, B. subtilis MB99 and B. amyloliquefaciens MB101 Brevibacillus laterosporus

Chitinases

Paenibacillus pasadenensis

Chitinases

Brevibacillus laterosporus

Chitinase, b-1,3-glucanase and protease

Volatile antimicrobial compounds and high enzymatic Paenibacillus ehimensis activities (chitinase, cellulase, glucanase and protease)

subsequently processed within the insect's gut, they are slowacting (in comparison to conventional chemicals). They associate bind to the receptor, a-glucosidase on the midgut microvilli, and cause lysis of midgut of the mosquito cells after internalization (Rahman et al., 2012). They are active against mosquito larvae under a wide range of conditions including extended residual activity in highly organic aquatic environments. Schwartz et al. (2001) demonstrated for the first time that the mosquitocidal binary toxin produced by B. sphaericus and its individual components permeabilize receptor-free large unilamellar phospholipid vesicles and planar lipid bilayers of the target larvae by a mechanism of pore formation. Furthermore, Nishiwaki et al. (2007) reported the exploitation of a novel insecticidal pore-forming toxin; B. sphaericus derived Sphaericolysin; active against a wide range of larvae.

M. incognita and Fusarium oxysporum f. sp. lycopersici

Wang et al., 2002 Kim and Chung 2004 Alvarez et al., 2011 Geetha et al., 2011 Yuan et al., 2012 Lucas Garcia et al., 2004 Jamalizadeh et al., 2008 Mendoza et al., 2008 Oliveira et al., 2009 Son et al., 2009

Fusarium graminearum, Alternaria alternata, Rhizoctonia Zhao et al., solani, Cryphonectria parasitica and Phytophthora capsici 2010 Meloidogyne incognita Huang et al., 2010 Leptosphaeria maculans Ramarathnam et al., 2011 Rhizoctonia solani Solanki et al., 2012 Plutella xylostella

Prasanna et al., 2013 Penicillium and Aspergillus Loni et al., 2014 Fusarium equiseti Prasanna et al., 2013 Fusarium oxysporum f. sp. lycopersici and Phytophthora Naing et al., capsici 2013

5. Other Bacillus sp. related biopesticide In addition to the described biopesticide, there is a great diversity of other bacterial derived biopesticide. Generally, bacteria belonging to Bacillus species including amyloliquefaciens, licheniformis, vallismortis and megaterium and Paenibacillus and Brevibacillus strains produce a large variety of biopesticides with antifungal, insecticidal and nematicidal activities. Table 3 presents a wide array of bioactive compounds along with their producing and antagonist strains. Bacillus amyloliquefaciens can be classified among the most recognized biopesticide producing bacteria. Literature reviews reported their phytopathogenic fungi suppressing ability through the production of active protein against Colletotrichum lagenarium (Kim and Chung, 2004). Similarly, cyclic lipopeptides iturin, surfactin and

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fengycin are effective in the biocontrol of sclerotinia stem rot disease (Alvarez et al., 2011), volatile compounds inhibit F. oxysporum f. sp. cubense growth and spore germination (Yuan et al., 2012) and chitinase enzyme are active against Micrococcus lysodeikticus (Wang et al., 2002). Also, Geetha et al. (2011) reported the mosquitocidal potency of B. amyloliquefaciens related biosurfactant against A. stephensi, C. quinquefasciatus and A. aegypti. Morover, greenhouse protection assays indicated 70% and 62% disease reductions respectively, over the infected control by B. amyloliquefaciens MB101- and B. subtilis MB14-treatment (Solanki et al., 2012). Bacillus licheniformis, having considerable colonisation and competitive ability and inducing the systemic resistance in tomato and pepper in greenhouse experiments against Xanthomonas campestris, could be used as a biofertiliser or biocontrol agent without altering normal growth of tomato and pepper plants (Lucas Garcia et al., 2004). It was described as efficient biological control agent of gray mold on apple fruits caused by Botrytis mali (Jamalizadeh et al., 2008). Furthermore, several Bacillus sp. strains are active against nematodes. Bacillus vallismortis ZZ185 producing a mixture of Bacillomycin D exhibited strong antifungal activity against the phytopathogens F. graminearum, Alternaria alternata, R. solani, Cryphonectria parasitica and P. capsici (Zhao et al., 2010). Previous reports discussed the nematicidal activity of Bacillus megaterium related volatiles (benzeneacetaldehyde, 2-nonanone, decanal, 2undecanone and dimethyl disulphide) against both juveniles and eggs of M. incognita (Huang et al., 2010). Mendoza et al. (2008) discussed the nematicidal activity of Bacillus firmus derived bioactive compounds against the burrowing nematode Radopholus similis, the root-knot nematode M. incognita and the stem nematode Ditylenchus dipsaci (Tylenchida: Anguinidae). Moreover, a wide variety of bacterial strains produced bioactive mycolytic enzymes including chitinase and glucanase that inhibits phytopathogenic fungi growth. Solanki et al. (2012) reported the production of chitinase, b-1,3-glucanase and protease by antagonistic bacteria suppressing R. solani rot namely, B. megaterium MB3, B. subtilis MB14, B. subtilis MB99 and B. amyloliquefaciens MB101. Loni et al. (2014) and Prasanna et al. (2013) reported the efficient antifungal activity of chitinases derived from Paenibacillus pasadenensis against Penicillium and Aspergillus and from Brevibacillus laterosporus against Fusarium equiseti. Moreover, Br. laterosporus derived chitinase have an insecticidal potential towards larvae of diamond back moths Plutella xylostella (Prasanna et al., 2013). The plant growth-promoting rhizobacteria, Pa. polymyxa and Pa. lentimorbus suppress disease complex caused by root-knot nematode M. incognita and F. oxysporum f. sp. lycopersici wilt fungus interactions on tomato (Son et al., 2009). Naing et al. (2013) characterized the antifungal activity of Pa. ehimensis against soil borne phytopathogenic fungi F. oxysporum f.sp. lycopersici and P. capsici probably due to the production of volatile antimicrobial compounds and bioactive enzymes (chitinase, cellulase, glucanase and protease). In another work, Pa. macerans was described to produce amino acids killing the rootknot nematode Meloidogyne exigua (Oliveira et al., 2009). Ramarathnam et al. (2011) reported the beneficial effect of antibiotic-producing Bacillus cereus strain DFE4 and B. amyloliquefaciens strain DFE16 in the control of blackleg in canola caused by the fungal pathogen Leptosphaeria maculans by elicitation of induced systemic resistance and direct antibiosis. 6. Pseudomonas sp. based biopesticides Pseudomonas genus includes a group of Gram-negative motile aerobic rods that are wide-spread throughout nature. They are among the most heterogeneous and ecologically significant group

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of known bacteria. They are characterized by elevated metabolic versatility, thanks to presence of a complex enzymatic system. Regarding literature reviews and studies, certain members of the genus Pseudomonas are considered to be important phytopathogens and agents or carriers of human infections whereas other strains and species exhibited activities of bioremediation and biocontrol. They are well recognized by the production of diverse biopesticides active against phytopathogenic fungi and plant pathogenic larvae and nematode. Table 4 enumerates a wide array of Pseudomonas derived bioactive compounds including biosurfactants, mycolytic enzymes, bacteriocins and secondary bioactive metabolites along with their producing and antagonist strains. 6.1. Antimicrobial activity of Pseudomonas derived biopesticides: involvement in plant protection 6.1.1. Antimicrobial activity of Pseudomonas derived biosurfactants Pseudomonas related lipopeptide and rhamnolipid are among the most powerful biosurfactants. They are involved in biocontrol field for their efficient antifungal activities. Pseudomonas sp. DSS73 exhibited antagonism towards the root-pathogenic microfungi Pythium ultimum and R. solani probably due to the production of the cyclic lipopeptide amphisin (Andersen et al., 2003). Cyclic lipononadepsipeptides, a member of the viscosin group produced by Pseudomonas putida RW10S2, inhibited the growth of the phytopathogenic Xanthomonas species (Rokni-Zadeh et al., 2012). Furthermore, Sha et al. (2012) reported the antifungal activity of Pseudomonas aeruginosa ZJU211 derived rhamnolipid towards plant pathogens comprising two Oomycetes, three Ascomycota and two Mucor spp. fungi. Sclerosin produced by Pseudomonas sp. DF41 was capable of suppressing Sclerotinia sclerotiorum-mediated stem rot of canola (Berry et al., 2012). Furthermore, rhamnolipid biosurfactants were evaluated as efficient agents for in vivo biocontrol against phytophthora blight and anthracnose disease caused by Phytophthora capsici and Colletotrichum orbiculare respectively (Kim et al., 2000) and the brown root rot disease of witloof chicory caused by Phytophthora cryptogea (De Jonghe et al., 2005). P. aeruginosa derived rhamnolipids enhanced the biocontrol potential of Rhodotorula glutinis towards A. alternate (Yan et al., 2014). Results showed an increase of fungi suppression and the stimulation of peroxidase, polyphenoloxidase and phenylalanine ammonialyase activities of cherry tomato fruit (Yan et al., 2014). 6.1.2. Antimicrobial activity of mycolytic enzymes and secondary active metabolites Furthermore, Pseudomonas sp. produced diverse metabolites including mycolytic enzymes and secondary active metabolites having the ability to reduce plant fungi growth and infection. In this aim, Pseudomonas chlororaphis M71 reduced drastically F. oxysporum f. sp. radicis-lycopersici pathogenicity on tomato plantlets by proteases, siderophores, phenazine, N-acyl homoserine lactones and antibiotics (Puopolo et al., 2011). Zhou et al. (2012) reported the inhibition of phytopathogenic bacteria Ralstonia solanacearum by the antimicrobial compounds produced by Pseudomonas brassicacearum J12 including 2,4-diacetylphloroglucinol, hydrogen cyanide, siderophores and protease. Susilomati et al. (2011) reported the screening of Pseudomonas sp. indigenous soybeans’ rhizobacteria possessing biocontrol characters against soilborne mainly i.e. S. rolfsii, F. oxysporum and R. solani, in vitro and in planta by the production of diverse metabolites including siderophore, chitinase and hydrogen cyanide. P. fluorescens exerted its antagonistic activity towards the crown rot pathogen A. niger in Arachis hypogaea L. through the production of mycolytic enzymes namely protease,

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Table 4 Pseudomonas sp. based biopesticides. Bioactive compound Antimicrobial activity Biosurfactant Rhamnolipid B Amphisin lipopeptide Rhamnolipid Massetolid Rhamnolipid Sclerosin Mycolytic enzymes and Secondary bioactive metabolites Mycolytic enzymes namely protease, lipase and secondary metabolites such as Hydrogen cyanide (HCN), Salicylic acid (SA) and iron chelating siderophores Proteases, siderophores, phenazine, N-acyl homoserine lactones and antibiotics Siderophore, chitinase and hydrogen cyanide 2,4-diacetylphloroglucinol (2,4-DAPG), hydrogen cyanide (HCN), siderophore(s) and protease Glucanase, protease and chitinase Glucanases and lipases Phenazines and siderophores of Redox-active pyocyanin

n-alkylated benzylamine Bacteriocins Bacteriocin Bacteriocin Lectin-like bacteriocin Insecticidal activity Exotoxin Rhamnolipids

Producing strain Antagonist strain

References

Pseudomonas aeruginosa B5 Pseudomonas sp. DSS73 Pseudomonas aeruginosa PRO1 P. fluorescens SS101 P. aeruginosa

Kim et al., 2000

Phytophthora capsici and Colletotrichum orbiculare Pythium ultimum and Rhizoctonia solani Phytophthora cryptogea Phytophthora infestans Botrytis cinerea

Pseudomonas sp. Sclerotinia sclerotiorum DF41 P. fluorescens

A. niger

P. syringae pv. ciccaronei Pseudomonas sp. BW11M1 P. fluorescens Pf5

P. syringae subsp. savastanoi

P. fluorescens

Aedes aegypti

Lavermicocca et al., 1999 Phytopathogenic fluorescent Pseudomonas de los Santos et al., 2005 Wide variety of phytopathogenic fungi and Parret et al., bacteria 2005

P. aeruginosa strain

P. aeruginosa strain

P. aeruginosa

Nematicidal activity Siderophores, salicylic acid, 2, 4-diacetylphloroglucinol (DAPG) and hydrogen cyanide Pseudomonas and extracellular protease species P. fluorescens strain P. fluorescens Fluorescent pseudomonads strains

P. fluorescens

2,4-diacetylphloroglucinol

P. fluorescens CHAO P. fluorescens CHAO P. fluorescens CHA0 P. aeruginosa PAO1

Protease Cyanide

lipase and secondary metabolites such as hydrogen cyanide, salicylic acid and iron chelating siderophores (Anand and Kulothungan, 2010). Pseudomonas sp. was effective as biocontrol

Varnier et al., 2009 Berry et al., 2012

Anand and Kulothungan 2010 P. chlororaphis Fusarium oxysporum f. sp. radicis-lycopersici Puopolo et al., M71 2011 Pseudomonas sp. Sclerotium rolfsii, Fusarium oxysporum, and Susilomati et al., Rhizoctonia solani 2011 Ralstonia solanacearum Zhou et al., 2012 P. brassicacearum J12 Pseudomonas sp. Collectotrichum gleosporioides, Alternaria Srividya et al., brassicola, A. brassiceae and A. alternate 2012 P. fluorescens Curvularia lunata, Fusarium oxysporum, A. Karnwal 2014 padwickii and Rhizoctonia solani P. chlororaphis Erwinia carotovora ssp. carotovara SCC1 Han et al., 2006 O6 P. aeruginosa Magnaporthe grisea De 7NSK2 Vleesschauwer et al., 2006 P. putida BTP1 Botrytis cinerea Ongena et al., 2005

P. aeruginosa LBI Aedes aegypti 2A1 P. aeruginosa Anopheles arabiensis

Pyoluteorin and cyanide

Andersen et al., 2003 De Jonghe et al., 2005 Tran et al., 2007

Bactrocera oleae

Lalithambika et al., 2014 Silva et al., 2014 Omoya and Akinyosoye 2011 Mostakim et al., 2012

Plant-parasitic nematodes

Khan et al., 2012

Rotylenchulus reniformis

Jayakumar et al., 2004 Khan et al., 2012

Helicotylenchus indicus, Xiphinema americanum and M. incognita. M. javanica M. javanica M. incognita Caenorhabditis elegans

Siddiqui and Shaukat 2003 Siddiqui et al., 2006 Siddiqui et al., 2005 Gallagher and Manoil 2001

agent against soil borne phytopathogens-Collectotrichum gleosporioides, Alternaria brassicola, A. brassiceae and A. alternate through the production of mycolytic enzymes; glucanase, protease and

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chitinase (Srividya et al., 2012). Karnwal (2014) reported the efficiency of a P. fluorescens strain in biocontrolling fungal phytopathogenic Curvularia lunata, F. oxysporum, Alternaria padwickii and R. solani through the production of glucanases and lipases mycolytic enzymes. Pseudomonas derived bacteriocins were described to combat against plant bacteria and fungi diseases. Lavermicocca et al. (1999) reported the efficient inhibitory effect of P. syringae pv. ciccaronei derived bacteriocin against strains of P. syringae subsp. savastanoi; the causal agent of olive knot disease. Also, de los Santos et al. (2005) reported the production of bacteriocin that inhibits the growth of some phytopathogenic fluorescent Pseudomonas by Pseudomonas sp. BW11M1. Parret et al. (2005) reported the production of a novel lectin-like bacteriocin by P. fluorescens Pf-5 active against a wide variety of phytopathogenic fungi and bacteria. 6.2. Inducing of systemic resistance in plants by Pseudomonas derived bioactive compounds Generally, Pseudomonas derived biosurfactants can be considered as plant immunity stimulators. P. aeruginosa derived rhamnolipid trigger strong defense responses in grapevine including early events of cell signaling like Ca2þ influx, reactive oxygen species production and MAP kinase activation (Varnier et al., 2009). They also induce a large battery of defense genes including some pathogenesis-related protein genes and genes involved in oxylipins and phytoalexins biosynthesis pathways (Varnier et al., 2009). P. fluorescens SS101 derived Massetolid induced systemic resistance in tomato permitting the biological control of tomato late blight caused by Phytophthora infestans (Tran et al., 2007). In addition to biosurfactants, others biomolecules produced by Pseudomonas sp. can induce systemic resistance in plants. Phenazines and siderophores of P. chlororaphis O6 induced the systemic resistance of tobacco against the soft-rot pathogen, E. carotovora ssp. carotovara SCC1 (Han et al., 2006). Moreover, P. aeruginosa 7NSK2 derived redoxactive pyocyanin triggered systemic resistance to Magnaporthe grisea in rice (De Vleesschauwer et al., 2006). Also, P. putida BTP1 derived n-alkylated benzylamine induced systemic resistance in bean (Ongena et al., 2005). 6.3. Insecticidal activity of Pseudomonas derived biopesticides In addition to antifungal potency, Pseudomonas sp. has a great opportunity for larvicidal activities. Lalithambika et al. (2014) reported the efficient biocontrol of the Dengue Vector A. aegypti (Diptera: Culicidae) using an exotoxin derived from P. fluorescens. Omoya and Akinyosoye (2011) and Mostakim et al. (2012) reported the larvicidal potency of P. aeruginosa strains on the Anopheles arabiensis (Diptera: Culicidae), the main malaria vector in Nigeria and the olive fruit fly Bactrocera oleae larvae (Diptera: Tephritidae) respectively. Silva et al. (2014) reported the larvicidal potency of P. aeruginosa LBI 2A1 derived rhamnolipids against A. aegypti larvae. 6.4. Nematicidal activity of Pseudomonas derived biopesticides Pseudomonas species were recognized by their antagonistic activities towards some plant-parasitic nematodes through the production of secondary active metabolites siderophores, salicylic acid, 2, 4-diacetylphloroglucinol and hydrogen cyanide and extracellular protease (Khan et al., 2012). Jayakumar et al. (2004) described the efficient biological control of cotton reniform nematode Rotylenchulus reniformis with P. fluorescens. Certain fluorescent pseudomonads were active against diverse plant-parasitic nematodes including Helicotylenchus indicus (Tylenchida: Hoplolaimidae), Xiphinema americanum (Dorylaimida: Longidoridae) and M.

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incognita (Khan et al., 2012). In vivo seed bacterization with the isolates suppressed galling caused by M. incognita in mungbean roots, reduced nematode populations and enhanced shoot weight (Khan et al., 2012). Also, literature reviews reported the nematicidal activity of P. fluorescens CHAO derived secondary metabolites; 2,4diacetylphloroglucinol and pyoluteorin and cyanide against rootknot nematode Meloidogyne javanica (Tylenchida: Heteroderidae) as described by Siddiqui and Shaukat (2003) and Siddiqui et al. (2006) respectively. Siddiqui et al. (2005) reported the efficient biocontrol of the root-knot nematode M. incognita during tomato and soybean infection by an extracellular protease derived from P. fluorescens CHA0. Also, P. aeruginosa PAO1 killed Caenorhabditis elegans (Rhabditida: Rhabditidae) by cyanide poisoning (Gallagher and Manoil, 2001). 7. Advantages and disadvantages of bacterial related biopesticides There is an urgent requirement for alternative tactics to help make crop protection more sustainable. Many experts promoted integrated pest management as the best way forward. Biopesticides are a particular group of crop protection tools used in integrated pest management. Microbial pesticides offered numerous advantages towards other groups of pesticides including those derived from fungi, plants and zooid (Chandler et al., 2011). Generally, the organisms used in microbial insecticides are essentially nontoxic and nonpathogenic to wildlife, humans and other organisms not closely related to the target pest (Chandler et al., 2011; Chakoosari, 2013). The safety offered by microbial insecticides is their greatest strength. In fact, the toxic action of microbial insecticides is often specific to a single group or species of insects, and this specificity means that most microbial insecticides do not directly affect beneficial insects (including predators or parasites of pests) in treated areas (Chandler et al., 2011; Chakoosari, 2013). Moreover, most microbial insecticides can be used in conjunction with synthetic chemical insecticides because in most cases the microbial product is not deactivated or damaged by residues of conventional insecticides (Chandler et al., 2011). Because their residues present no hazards to humans or other animals, microbial insecticides can be applied even when a crop is almost ready for harvest. In some cases, the pathogenic microorganisms can become established in a pest population or its habitat and provide control during subsequent pest generations or seasons (Chandler et al., 2011; Chakoosari, 2013). They also enhance the root and plant growth by way of encouraging the beneficial soil microflora (Berg, 2009). By this way they take part in the increase of the crop yield. However, microbial pesticides have some disadvantages. Naturally there are also the limitations which are listed below, but do not prevent the successful use of microbial insecticides. These factors just provide users to choose effective microbial products and take necessary steps to achieve successful results. Having a higher efficiency, each application may control only a portion of the pests present in a field and garden. If other types of pests are present in the treated area, they will survive and may continue to cause damage. Moreover, heat, desiccation (drying out), or exposure to ultraviolet radiation reduced the effectiveness of several types of microbial insecticides. Consequently, proper timing and application procedures are especially important for some products (Chandler et al., 2011). Special formulation and storage procedures are necessary for some microbial pesticides (Chandler et al., 2011). Although these procedures may complicate the production and distribution of certain products, storage requirements do not seriously limit the handling of microbial insecticides that are widely available. Because several microbial insecticides are pest-specific, the potential market for these products may be limited (Chandler et al., 2011).

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8. Conclusion In recent years, many new functions in protecting plants from pathogen infection have been discovered. Nature offers a wide variety of bacterial related biopesticides. Appropriate and target specific inhibition of harmful pests (phytopathogenic fungi and undesirable insects) depends upon the availability of highly active and stable biopesticides preparations. Bacillus and Pseudomonas related biopesticides are among the most recognized bioactive agents. B. thuringiensis related toxins and bacterial surfactants are effectively applied for the biocontrol of phytopathogenic fungi invasion, killing nefaste larvae and nematodes. Over the past decade, with the rapid development of new techniques gradually improving the biopesticides production such as molecular biology, genetic and protein engineering, fermentation technology, the field had developed excellent application prospects. Therefore, the research and application of biopesticides had been well developed and biopesticides gradually replaced the chemical pesticides in the market. They became ideal substitutes for their traditional chemical counterparts in pollution-free agricultural production. Altogether, the use of microorganisms and the exploitation of beneficial plantemicrobe interactions offered promising and environmentally friendly strategies for conventional and organic agriculture worldwide. Conflicts of interest No conflicts of interest are declared. Acknowledgments This work has been supported by grants from ‘‘Tunisian Ministry of Higher Education, Scientific Research and Technology” and the “Tunisian Ministry of Agriculture”. References Abdelkefi-Mesrati, L., Boukedi, H., Chakroun, M., Kamoun, F., Azzouz, H., Tounsi, S., Rouis, S., Jaoua, S., 2011. Investigation of the steps involved in the difference of susceptibility of Ephestia kuehniella and Spodoptera littoralis to the Bacillus thuringiensis Vip3Aa16 toxin. J. Invert. Pathol. http://dx.doi.org/10.1016/ j.jip.2011.05.014. Abudulai, M., Shepard, B.M., Mitchell, P.L., 2001. Parasitism and predation on eggs of Leptoglossus phyllopus (L.) (Hemiptera: Coreidae) in Cowpea: impact of endosulfan sprays. J. Agr. Urban Entomol. 18, 105e115. Alvarez, F., Castro, M., Principe, A., Borioli, G., Fischer, S., Mori, G., Jofre, E., 2011. The plant-associated Bacillus amyloliquefaciens strains MEP218 and ARP23 capable of producing the cyclic lipopeptides iturin or surfactin and fengycin are effective in biocontrol of sclerotinia stem rot disease. J. Appl. Microbiol. 112, 159e174. Anand, R., Kulothungan, S., 2010. Antifungal metabolites of Pseudomonas fluorescens against Crown rot pathogen of Arachis Hypogaea. Ann. Biol. Res. 1, 199e207. Andersen, J.B., Koch, B., Nielsen, T.H., Sørensen, D., Hansen, M., Nybroe, O., Christophersen, C., Sørensen, J., Molin, S., Givskov, M., 2003. Surface motility in Pseudomonas sp. DSS73 is required for efficient biological containment of the root-pathogenic microfungi Rhizoctonia solani and Pythium ultimum. Microbiology 149, 37e46. Ashwini, N., Srividya, S., 2014. Potentiality of Bacillus subtilis as biocontrol agent for management of anthracnose disease of chilli caused by Colletotrichum gloeosporioides OGC1. Biotechnol 4, 127e136. Assie, L.K., Deleu, M., Arnaud, L., Paquot, M., Thonart, P., Gaspar, Ch, Haubruge, E., 2002. Insecticide activity of surfactins and iturins from a biopesticide Bacillus subtilis Cohn (S499 strain). Meded. Rijksuniv. Gent. Fak. Landbouwkd. Toegep. Biol. Wet. 67, 647e655. Beard, C.E., Court, L., Boets, A., Mourant, R., Rie, J.V., Akhurst, R.J., 2008. Unusually high frequency of genes encoding vegetative insecticidal proteins in an Australian Bacillus thuringiensis collection. Curr. Microbiol. 57, 195e199. Berg, G., 2009. Plantemicrobe interactions promoting plant growth and health: perspectives for controlled use of microorganisms in agriculture. Appl. Microbiol. Biotechnol. 84, 11e18. Berry, C.L., Brassinga, A.K.C., Loewen, P.C., de Kievit, T.R., 2012. Chemical and biological characterization of sclerosin, an antifungal lipopeptide. Can. J. Microbiol. 58, 1027e1034. Chakoosari, M.M.D., 2013. Efficacy of various biological and microbial insecticides.

J. Biol. Today's World 2, 249e254. Chandler, D., Bailey, A.S., Tatchell, G.M., Davidson, G., Greaves, J., Grant, W.P., 2011. The development, regulation and use of biopesticides for integrated pest management. Philos. Trans. R. Soc. Lond. B Biol. Sci. 366, 1987e1998. Chen, F., Wang, M., Zheng, Y., Luo, J., Yang, X., Wang, X., 2010. Quantitative changes of plant defense enzymes and phytohormone in biocontrol of cucumber Fusarium wilt by Bacillus subtilis B579. World J. Microbiol. Biotechnol. 26, 675e684. Cheng, X.L., Liu, C.J., Yao, J.W., 2010. The current status, development trend and strategy of the bio-pesticide Industry in China. Hubei. Agric. Sci. 49, 2287e2290. Cherif, A., Rezgui, W., Raddadi, N., Daffonchio, D., Boudabous, A., 2008. Characterization and partial purification of entomocin 110, a newly identified bacteriocin from Bacillus thuringiensis subsp. entomocidus HD110. Microbiol. Res. 163, 684e692. Chitarra, G.S., Breeuwer, P., Nout, M.J.R., van Aelst, A.C., Rombouts, F.M., Abee, T., 2003. An antifungal compound produced by Bacillus subtilis YM 10e20 inhibits germination of Penicillium roqueforti conidiospores. J. Appl. Microbiol. 94, 159e166. Craveiro, K.I.C., Gomes Júnior, J.E., Silva, M.C.M., Macedo, L.L.P., Lucena, W.A., ~es, M.T.Q., Silva, M.S., de Souza Júnior, J.D.A., Oliveira, G.R., de Magalha Santiago, A.D., Grossi-de-Saa, M.F., 2010. Variant Cry1Ia toxins generated by DNA shuffling are active against sugarcane giant borer. J. Biotechnol. 145, 215e221. Das, K., Mukherjee, A.K., 2006. Assessment of mosquito larvicidal potency of cyclic lipopeptides produced by Bacillus subtilis strains. Acta Trop. 97, 168e173. € fte, M., 2005. Control of PhytophDe Jonghe, K., De Dobbelaere, I., Sarrazyn, R., Ho thora cryptogea in the hydroponic forcing of witloof chicory with the rhamnolipid-based biosurfactant formulation PRO1. Plant Pathol. 54, 219e226. de los Santos, P.E., Parret, A.H.A., De Mot, R., 2005. Stress-related Pseudomonas genes involved in production of bacteriocin LlpA. FEMS Microbiol. Lett. 244, 243e250. de Souza Aguiar, R.W., Martins, E.S., Ribeiro, B.M., Monnerat, R.G., 2012. Cry10Aa protein is highly toxic to Anthonomus grandis boheman (Coleoptera: Curculionidae), an important insect pest in Brazilian cotton crop Fields. Bt. Res. http:// dx.doi.org/10.5376/bt.2012.03.0004. €fte, M., 2006. Redox-active pyocyanin secreted De Vleesschauwer, D., Cornelis, P., Ho by Pseudomonas aeruginosa 7NSK2 triggers systemic resistance to Magnaporthe grisea but enhances Rhizoctonia solani susceptibility in rice. Mol. PlanteMicrobe Interact. 19, 1406e1419. Dong, Y.H., Zhang, X.F., Xu, J.L., Zhang, L.H., 2004. Insecticidal Bacillus thuringiensis silences Erwinia carotovora virulence by a new form of microbial antagonism, signal interference. Appl. Environ. Microbiol. 70, 954e960. Donovan, W.P., Engleman, J.T., Donovan, J.C., Baum, J.A., Bunkers, G.J., Chi, D.J., Clinton, W.P., English, L., Heck, G.R., Ilagan, O.M., Krasomil-Osterfeld, K.C., Pitkin, J.W., Roberts, J.K., Walters, M.R., 2006. Discovery and characterization of Sip1A: a novel secreted protein from Bacillus thuringiensis with activity against coleopteran larvae. Appl. Microbiol. Biotechnol. 72, 713e719. Ekobu, M., Solera, M., Kyamanywa, S., Mwanga, R.O.M., Odongo, B., Ghislain, M., Moar, W.J., 2010. Toxicity of seven Bacillus thuringiensis cry proteins against Cylas puncticollis and Cylas brunneus (Coleoptera: brentidae) using a novel artificial diet. J. Econ. Entomol. 103, 1493e1502. Eswarapriya, B., Gopalsamy, B., Kameswari, B., Meera, R., Devi, P., 2010. Insecticidal activity of Bacillus thuringiensis IBT- 15 strain against Plutella xylostella. Int. J. Pharm. Tech. Res. 2, 2048e2053. Fang, J., Xu, X., Wang, P., Zhao, J.-Z., Shelton, A.M., Cheng, J., Feng, M.G., Shen, Z., 2007. Characterization of chimeric Bacillus thuringiensis Vip3 toxins. Appl. Environ. Microbiol. 73, 956e961. Gallagher, L.A., Manoil, C., 2001. Pseudomonas aeruginosa PAO1 kills Caenorhabditis elegans by cyanide poisoning. J. Bacteriol. 183, 6207e6214. Gathmann, A., Priesnitz, K.U., 2014. How susceptible are different lepidopteran/ coleopteran maize pests to Bt-proteins: a systematic review protocol. Environ. Evid. 3, 12. Geetha, Manonmani, A.M., Prabakaran, G., 2011. Bacillus amyloliquefaciens: a mosquitocidal bacterium from mangrove forests of Andaman & Nicobar islands, India. Acta Trop. 120, 155e159. Geetha, I., Manonmani, A.M., 2008. Mosquito pupicidal toxin production by Bacillus subtilis subsp. subtilis. Biol. Control 44, 242e247. Geetha, I., Manonmani, A.M., Paily, K.P., 2010. Identification and characterization of a mosquito pupicidal metabolite of a Bacillus subtilis subsp. subtilis strain. Appl. Microbiol. Biotechnol. 86, 1737e1744. Ghribi, D., Abdelkefi-Mesrati, L., Boukedi, H., Elleuch, M., Ellouze-Chaabouni, S., Tounsi, S., 2012a. The impact of the Bacillus subtilis SPB1 biosurfactant on the midgut histology of Spodoptera littoralis (Lepidoptera: Noctuidae) and determination of its putative receptor. J. Invertebr. Pathol. 109, 183e186. Ghribi, D., Elleuch, M., Abdelkefi, L., Ellouze-Chaabouni, S., 2012b. Evaluation of larvicidal potency of Bacillus subtilis SPB1 biosurfactant against Ephestia kuehniella (Lepidoptera: Pyralidae) larvae and influence of abiotic factors on its insecticidal activity. J. Stored Prod. Res. 48, 68e72. Ghribi, D., Mnif, I., Boukedi, H., Kammoun, R., Ellouze-Chaabouni, S., 2011. Statistical optimization of low-cost medium for economical production of Bacillus subtilis biosurfactant, a biocontrol agent for the olive moth Prays oleae. Afr. J. Microbiol. Res. 5, 4927e4936. Gokte, N., Swarup, G., 1988. On the potential of some bacterial against root-knot and cyst nematodes. Ind. J. Nematol. 18, 152e153. Hammami, I., Rhouma, A., Jaouadi, B., Rebai, A., Nesme, X., 2009. Optimization and biochemical characterization of a bacteriocin from a newly isolated Bacillus

I. Mnif, D. Ghribi / Crop Protection 77 (2015) 52e64 subtilis strain 14B for biocontrol of Agrobacterium spp. strains. Lett. Appl. Microbiol. 48, 253e260. Hammami, I., Triki, M.A., Rebai, A., 2011. Purification and characterization of the novel bacteriocin Bac IH7 with antifungal and antibacterial properties. J. Plant Pathol. 93, 443e454. Han, S.H., Anderson, A.J., Yang, K.Y., Cho, B.H., Kim, K.Y., Lee, M.C., Kim, Y.H., Kim, Y.C., 2006. Multiple determinants influence root colonization and induction of induced systemic resistance by Pseudomonas chlororaphis O6. Mol. Plant Pathol. 7, 463e472. Hathout, Y., Ho, Y.P., Ryzhov, V., Demirev, P., Fenselau, C., 2000. Kurstakins: a new class of lipopeptides isolated from Bacillus thuringiensis. J. Nat. Prod. 63, 1492e1496. Hire, R.S., Hadapad, A.B., Dongre, T.K., Kumar, V., 2009. Purification and characterization of mosquitocidal Bacillus sphaericus BinA protein. J. Invertebr. Pathol. 101, 106e111. Hire, R.S., Hadapad, A.B., Vijayalakshmi, N., Tanaji, K., 2010. Characterization of highly toxic indigenous strains of mosquitocidal organism Bacillus sphaericus Dongre. FEMS Microbiol. Lett. 305, 155e161. Huang, Y., Xu, C.K., Ma, L., Zhang, K.Q., Duan, C.Q., Mo, M.H., 2010. Characterisation of volatiles produced from Bacillus megaterium YFM3.25 and their nematicidal activity against Meloidogyne incognita. Eur. J. Plant Pathol. 126, 417e422. Jamalizadeh, M., Etebarian, H.R., Alizadeh, A.I., Aminian, H., 2008. Biological control of Gray mold on apple fruits by Bacillus licheniformis (EN74-1). Phytoparasitica 36, 23e29. Jayakumar, J., Ramakrishnan, S., Rajendran, G., 2004. Biological control of cotton reniform nematode, Rotylenchulus reniformis with Pseudomonas fluorescens. Ind. J. Nematol. 34, 230e231. Jisha, V.N., Smitha, R.B., Benjamin, S., 2013. An overview on the crystal toxins from Bacillus thuringiensis. Adv. Microbiol. 3, 462e472. Jonathan, E.I., Umamaheswari, R., 2006. Biomanagement of nematodes infesting banana by bacterial Endophytes (Bacillus subtilis). Ind. J. Nematol. 36, 213e216. Jones, G.W., Wirth, M.C., Monnerat, R.G., Berry, C., 2008. The Cry48Aa-Cry49Aa binary toxin from Bacillus sphaericus exhibits highly restricted target specificity. Environ. Microbiol. 10, 2418e2424. Kamenek, L.K., Kamenek, D.V., Terpilowski, M.A., Gouli, V.V., 2012. Antifungal action of Bacillus thuringiensis delta-endotoxin against pathogenic fungi related to Phytophthora and Fusarium. J. Agric. Technol. 8, 191e203. Kamoun, F., Ben Fguira, I., Ben Hassen, N.B., Mejdoub, H., Lereclus, D., Jaoua, S., 2011. Purification and characterization of a new Bacillus thuringiensis bacteriocin active against Listeria monocytogenes, Bacillus cereus and Agrobacterium tumefaciens. Appl. Biochem. Biotechnol. 165, 300e314. Karnwal, A., 2014. Mycolytic effect of fluorescent Pseudomonas in biocontrolling of fungal phytopathogenic Curvularia lunata, Fusarium oxysporum, Alternaria padwickii and Rhizoctonia solani. Arch. Phytopathol. Plant Prot. 44, 1128e1134. Kavitha, P.G., Jonathan, E.I., Nakkeeran, S., 2012. Effects of crude antibiotic of Bacillus subtilis on hatching of eggs and mortality of juveniles of Meloidogyne incognita. Nematol. Mediterr. 40, 203e206. Khan, A., Shaukat, S.S., Islam, S., Khan, A., 2012. Evaluation of fluorescent pseudomonad isolates for their activity against some plant-parasitic nematodes. AmEuras. J. Agric. Environ. Sci. 12, 1496e1506. Kim, B.S., Lee, J.Y., Hwang, B.K., 2000. In vivo control and in vitro antifungal activity of rhamnolipid B, a glycolipid antibiotic, against Phytophthora capsici and Colletotrichum orbiculare. Pest Manag. Sci. 56, 1029e1035. Kim, P.I., Bai, H., Chae, H., Chung, S., Kim, Y., Park, Y., Chi, Y.-T., 2004. Purification and characterization of a lipopeptide produced by Bacillus thuringiensis CMB26. J. Appl. Microbiol. 97, 942e949. Kim, P.I., Chung, K.-C., 2004. Production of an antifungal protein for control of Colletotrichum lagenarium by Bacillus amyloliquefaciens MET0908. FEMS Microbiol. Lett. 234, 177e183. Kita, N., Ohya, T., Uekusa, H., Nomura, K., Manago, M., Shoda, M., 2005. Biological control of damping-off of tomato seedlings and cucumber phomopsis root rot by Bacillus subtilis RB14-C. Jpn. Agric. Res. Q. 39, 109e114. Kotze, A.C., O'Grady, J., Gough, J.M., Pearson, R., Bagnall, N.H., Kemp, D.H., Akhurst, R.J., 2005. Toxicity of Bacillus thuringiensis to parasitic and free-living life-stages of nematode parasites of livestock. Int. J. Parasitol. 35, 1013e1022. Lalithambika, B., Vani, C., Tittes, A.N., 2014. Biological control of dengue vector using Pseudomonas fluorescens. Res. J. Rec. Sci. 3, 344e351. Lavermicocca, P., Lonigro, S.L., Evidente, A., Andolfi, A., 1999. Bacteriocin production by Pseudomonas syringae pv. ciccaronei NCPPB2355. Isolation and partial characterization of the antimicrobial compound. J. Appl. Microbiol. 86, 257e265. Li, X.Q., Wei, J.Z., Tan, A., Aroian, R.V., 2007. Resistance to root-knot nematode in tomato roots expressing a nematicidal Bacillus thuringiensis crystal protein. Plant Biotechnol. J. 5, 455e464. Li, X.-Q., Tan, A., Voegtline, M., Bekele, S., Chen, C.-S., Aroian, R.V., 2008. Expression of Cry5B protein from Bacillus thuringiensis in plant roots confers resistance to root-knot nematode. Biol. Control 47, 97e102. Lin, H.F., Chen, T.H., Liu, S.D., 2010. Bioactivity of antifungal substance iturin A produced by Bacillus subtilis strain BS-99-H against Pestalotiopsis eugeniae, a causal pathogen of wax apple fruit rot. Plant Pathol. Bull. 19, 225e233. Liu, B., Huang, L., Buchenauer, H., Kang, Z., 2010. Isolation and partial characterization of an antifungal protein from the endophytic Bacillus subtilis strain EDR4. Pest Biochem. Physiol. 98, 305e311. Liu, D., Chen, Y., Cai, J., Xiao, L., Liu, C., 2009. Chitinase B from Bacillus thuringiensis and its antagonism and insecticidal enhancing potential. Acta Microbiol. Sin. 49, 180e185.

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Liu, X., Ruan, L., Peng, D., Li, L., Sun, M., Yu, Z., 2014. Thuringiensi: a thermostable secondary metabolite from Bacillus thuringiensis with insecticidal activity against a wide range of insects. Toxins 6, 2228e2229. Loni, P.P., Patil, J.U., Phugare, S.S., Bajekal, S.S., 2014. Purification and characterization of alkaline chitinase from Paenibacillus pasadenensis NCIM 5434. J. Basic Microbiol. 53, 1e10. Lucas Garcia, J.A., Probanza, A., Ramos, B., 2004. Effect of inoculation of Bacillus licheniformis on tomato and pepper. Agronomie 24, 169e176. Lucon, C.M.M., Guzzo, S.D., De Jesus, C.O., Pascholati, S.F., De Goes, A., 2010. Postharvest harpin or Bacillus thuringiensis treatments suppress citrus black spot in 'Valencia' oranges. Crop Prot. 29, 766e772. Lysyk, T.J., 2006. Abundance and species composition of culicoides (Diptera: Ceratopogonidae) at cattle facilities in southern Alberta, Canada. J. Med. Entomol. 43, 840e849. Lysyk, T.J., Kalischuk-Tymensen, L.D., Rochon, K., Selinger, L.B., 2010. Activity of Bacillus thuringiensis isolates against immature horn fly and stable fly (Diptera: muscidae). J. Econ. Entomol. 103, 1019e1029. Malik, K., Riazuddin, S., 2006. Immunoassay-based approach for detection of novel Bacillus thuringiensis-endotoxins, entomocidal to cotton aphids (Aphis gossypii) and whiteflies (Bemisia tabaci). Pak. J. Bot. 38, 757e765. Manonmani, A.M., Geetha, I., Bhuvaneswari, S., 2011. Enhanced production of mosquitocidal cyclic lipopeptide from Bacillus subtilis subsp. subtilis. Ind. J. Med. Res. 134, 476e482. Mendoza, A.R., Kiewnick, S., Sikora, R.A., 2008. In vitro activity of Bacillus firmus against the burrowing nematode Radopholus similis, the root-knot nematode Meloidogyne incognita and the stem nematode Ditylenchus dipsaci. Biocontrol Sci. Technol. 18, 377e389. Mnif, I., Elleuch, M., Ellouze Chaabouni, S., Ghribi, D., 2013. Bacillus subtilis SPB1 biosurfactant: production optimization and insecticidal activity against the carob moth Ectomyelois ceratoniae. Crop Prot. 50, 66e72. Mohammadipour, M., Mousivand, M., Jouzani, G.S., Abbasalizadeh, S., 2009. Molecular and biochemical characterization of Iranian surfactin-producing Bacillus subtilis isolates and evaluation of their biocontrol potential against Aspergillus flavus and Colletotrichum gloeosporioides. Can. J. Microbiol. 55, 395e404. Mohammed, S.H., El Saedy, M.A., Enan, M.R., Ibrahim, N.E., Ghareeb, A., Moustafa, S.A., 2008. Biocontrol efficiency of Bacillus thuringiensis toxins against root-knot nematode, Meloidogyne incognita. J. Cell. Mol. Biol. 7, 57e66. Mostakim, M., Soumya, E., Mohammed, I.H., Ibnsouda, S.K., 2012. Biocontrol potential of a Pseudomonas aeruginosa strain against Bactrocera oleae. Afr. J. Microbiol. Res. 6, 5472e5478. Naing, K.W., Anees, M., Kim, S.J., Nam, Y., Kim, Y.C., Kim, K.Y., 2013. Characterization of antifungal activity of Paenibacillus ehimensis KWN38 against soilborne phytopathogenic fungi belonging to various taxonomic groups. Ann. Microbiol. http://dx.doi.org/10.1007/s13213-013-0632-y. Nishiwaki, H., Nakashima, K., Ishida, C., Kawamura, T., Matsuda, K., 2007. Cloning, functional characterization, and mode of action of a novel insecticidal poreforming toxin, sphaericolysin, produced by Bacillus sphaericus. Appl. Environ. Microbiol. 73, 3404e3411. Oliveira, D.F., Carvalho, H.W.P., Nunes, A.S., Silva, G.H., Campos, V.P., Júnior, H.M.S., Cavalheiro, A.J., 2009. The activity of amino acids produced by Paenibacillus macerans and from commercial sources against the root-knot nematode Meloidogyne exigua. Eur. J. Plant Pathol. 124, 57e63. Omoya, F.O., Akinyosoye, F.A., 2011. Evaluation of larvicidal potency of some entomopathogenic bacteria isolated from insect cadavars on Anopheles arabiensis larvae in Nigeria. Int. J. Pharm. Biomed. Res. 2, 145e148. Ongena, M., Henry, G., Thonart, P., 2010. The roles of cyclic lipopeptides in the biocontrol activity of Bacillus subtilis. Rec. Dev. Manag. Plant Dis. Plant Pathol. 1, 59e66, 21st Century. Ongena, M., Jacques, P., 2007. Bacillus lipopeptides: versatile weapons for plant disease biocontrol. Trends Microbiol. 16, 115e125. Ongena, M., Jourdan, E., Sch€ afer, M., Kech, C., Budzikiewicz, H., Luxen, A., Thonart, P., 2005. Isolation of an N-alkylated benzylamine derivative from Pseudomonas putida BTP1 as elicitor of induced systemic resistance in bean. Mol. Plant Microbe Interact. 18 (6), 562e569. Organisation for Economic Co-operation and Development, 2009. Report of Workshop on the Regulation of Biopesticides: Registration and Communication Issues. See. Series on Pesticides No. 448. http://www.oecd.org/dataoecd/3/ Collego55/43056580.pdf. Park, H.-W., Bideshi, D.K., Federici, B.A., 2010. Properties and applied use of the mosquitocidal bacterium, Bacillus sphaericus. J. Asia-Pacific Entomol. 13, 159e168. Parret, A.H.A., Temmerman, K., De Mot, R., 2005. Novel lectin-like bacteriocins of biocontrol strain Pseudomonas fluorescens Pf-5. Appl. Environ. Microbiol. 71, 5197e5207. Peng, D., Chai, L., Wang, F., Zhang, F., Ruan, L., Sun, M., 2011. Synergistic activity between Bacillus thuringiensis Cry6Aa and Cry55Aa toxins against Meloidogyne incognita. Microb. Biotechnol. 4, 794e798. Prasanna, L., Eijsink, V.G.H., Meadow, R., Gåseidnes, S., 2013. A novel strain of Brevibacillus laterosporus produces chitinases that contribute to its biocontrol potential. Appl. Microbiol. Biotechnol. 97, 1601e1611. Puopolo, G., Raio, A., Pierson, L.S., Zoina, A., 2011. Selection of a new Pseudomonas chlororaphis strain for the biological control of Fusarium oxysporum f. sp. radicislycopersici. Phytopathol. Med. 50, 228e235. Raddadi, N., Belaouis, A., Tamagnini, I., Hansen, B.M., Hendriksen, N.B., Boudabous, A., Cherif, A., Daffonchio, D., 2009. Characterization of polyvalent

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I. Mnif, D. Ghribi / Crop Protection 77 (2015) 52e64

and safe Bacillus thuringiensis strains with potential use for biocontrol. J. Basic Microbiol. 49, 293e303. Rahman, M.A., Khan, S.A., Sultan, M.T., Islam, M.R., 2012. Characterization of Bacillus sphaericus binary proteins for biological control of Culex quinquefasciatus mosquitoes: a review. Int. J. Biosci. 2, 1e13. Ramarathnam, R., Dilantha Fernando, W.G., de Kievit, T., 2011. The role of antibiosis and induced systemic resistance, mediated by strains of Pseudomonas chlororaphis, Bacillus cereus and B. amyloliquefaciens, in controlling blackleg disease of canola. BioControl 56, 225e235. Reyes-Ramirez, A., Escudero-Abarca, B.I., Aguilar-Uscanga, G., Hayward-Jones, P.M., Eleazar Barboza-Corona, J., 2004. Antifungal activity of Bacillus thuringiensis chitinase and its potential for the biocontrol of phytopathogenic fungi in soybean seeds. J. Food Sci. 69, 131e134. Rokni-Zadeh, H., Li, W., Sanchez-Rodriguez, A., Sinnaeve, D., Rozenski, J., Martins, J.C., De Mot, R., 2012. Genetic and functional characterization of cyclic lipopeptide White-Line-Inducing Principle (WLIP) production by Rice rhizosphere isolate Pseudomonas putida RW10S2. Appl. Environ. Microbiol. 78, 4826. Rosas-García, N.M., 2009. Biopesticide production from Bacillus thuringiensis: an environmentally friendly alternative. Recent Pat. Biotechnol. 3, 28e36. Ruiz, L.M., Segura, C., Trujillo, J., Orduz, S., 2004. In vivo binding of the Cry11Bb toxin of Bacillus thuringiensis subsp. Medellin to the midgut of mosquito larvae (Diptera: Culicidae). Mem. Inst. Oswaldo Cruz 99, 73e79. Rungrod, A., Tjahaja, N.K., Soonsanga, S., Audtho, M., Promdonkoy, B., 2009. Bacillus sphaericus Mtx1 and Mtx2 toxins co-expressed in Escherichia coli are synergistic against Aedes aegypti larvae. Biotechnol. Lett. 31, 551e555. Schünemann, R., Knaak, N., Fiuza, L.D., 2014. Mode of action and specificity of Bacillus thuringiensis toxins in the control of caterpillars and stink bugs in soybean culture. ISRN Microbiol. 2014, 135675. Schwartz, J.-L., Potvin, L., Coux, F., Charles, J.-F., Berry, C., Humphreys, M.J., Jones, A.F., Bernhart, I., Dalla Serra, M., Menestrina, G., 2001. Permeabilization of model lipid membranes by Bacillus sphaericus mosquitocidal binary toxin and its individual components. J. Membr. Biol. 184, 171e183. Serpil, U., Sezen, K., Kati, H., Demirbag, Z., 2013. Purification and characterization of the bacteriocin Thuricin Bn1 produced by Bacillus thuringiensis subsp. kurstaki Bn1 isolated from a Hazelnut pest. J. Microbiol. Biotechnol. 23, 167e176. Sha, R., Jiang, L., Meng, Q., Zhang, G., Song, Z., 2012. Producing cell-free culture broth of rhamnolipids as a cost-effective fungicide against plant pathogens. J. Basic Microbiol. 52, 458e466. Shingote, P.R., Moharil, M.P., Dhumale, D.R., Jadhav, P.V., Satpute, N.S., Dudhare, M.S., 2013. Screening of vip1/vip2 binary toxin gene and its isolation and cloning from local Bacillus thuringiensis isolates. Sci. Asia 39, 620e624. Siddiqui, I.A., Haas, D., Heeb, S., 2005. Extracellular protease of Pseudomonas fluorescens CHA0, a biocontrol factor with activity against the root-knot nematode Meloidogyne incognita. Appl. Environ. Microbiol. 71, 5646e5649. Siddiqui, I.A., Shaukat, S.S., 2003. Suppression of root-knot disease by Pseudomonas fluorescens CHAO in tomato: importance of bacterial secondary metabolite 2,4diacetylphloroglucinol. Soil Biol. Biochem. 35, 1615e1623. Siddiqui, I.A., Shaukat, S.S., Sheikh, I.H., Khan, A., 2006. Role of cyanide production by Pseudomonas fluorescens CHA0 in the suppression of root-knot nematode, Meloidogyne javanica in tomato. World J. Microbiol. Biotechnol. 22, 641e650. Silva, V.L., Lovaglio, R.B., Von Zuben, C.J., Contiero, J., 2014. Larvicidal activity of rhamnolipids produced by Pseudomonas aeruginosa LBI 2A1 against Aedes aegypti larvae. In: Conf. Soc. Ind. Microbiol. Biotechnol. July 20e24, 2014; St. Louis, MO. Singh, G., Bhalla, A., Singh Bhatti, J., Chandel, S., Rajput, A., Abdullah, A., Andrabi, W., Kaur, P., 2014. Potential of chitinases as a biopesticide against agriculturally harmful fungi and insects. Res. Rev. J. Microbiol. Biotechnol. 3, 27e32. Solanki, M.K., Robert, A.S., Singh, R.K., Kumar, S., Pandey, A.K., Srivastava, A.K., Arora, D.K., 2012. Characterization of mycolytic enzymes of Bacillus strains and their Bio-Protection role against Rhizoctonia solani in tomato. Curr. Microbiol. 65, 330e336. Son, S.H., Khan, Z., Kim, S.G., Kim, Y.H., 2009. Plant growth-promoting rhizobacteria, Paenibacillus polymyxa and Paenibacillus lentimorbus suppress disease complex caused by root-knot nematode and fusarium wilt fungus. J. Appl. Microbiol. 107, 524e532. Srividya, S., Ramyasmruthi, S., Pallavi, O., Pallavi, S., Tilak, K., 2012. Mycolytic enzymes of fluorescent Pseudomonas sp. R as effective biocontrol against Colletotrichum gloeosporoides OGC1. Asiat. J. Biotechnol. Resour. 3, 1425e1433. Susilomati, A., Wahyudi, A.T., Lestari, Y., Suwanto, A., Wiyono, S., 2011. Potential Pseudomonas isolated from soybean rhizosphere as biocontrol against soil

borne phytopathogenic fungi. J. Biosci. 18, 51e56. Tareq, F.S., Lee, M.A., Lee, H.-S., Lee, Y.-J., Lee, J.S., Hasan, C.M., Islam, M.T., Shin, H.J., 2014. Gageotetrins A
C, Noncytotoxic antimicrobial linear lipopeptides from a Marine bacterium Bacillus subtilis. Org. Lett. 16, 928e931. Thakaew, R., Niamsup, H., 2013. Inhibitory activity of Bacillus subtilis BCC 6327 metabolites against growth of aflatoxigenic fungi isolated from bird chili powder. Int. J. Biosci. Biochem. Bioinf 3, 27e32. Thakore, Y., 2006. The biopesticide market for global agricultural use. Ind. Biotechnol. 23, 192e208. €fte, M., Raaijmakers, J.M., 2007. Role of the cyclic Tran, H., Ficke, A., Asiimwe, T., Ho lipopeptide massetolide A in biological control of Phytophthora infestans and in colonization of tomato plants by Pseudomonas fluorescens. New Phytol. 175, 731e742. Van Driesche, R., Hoddle, M., Center, T., 2008. Control of Pests and Weeds by Natural Enemies: an Introduction to Biological Control. Blackwell Publishing, Oxford, UK. van Frankenhuyzen, K., Tonon, A., 2013. Activity of Bacillus thuringiensis cyt1Ba crystal protein against hymenopteran forest pests. J. Invert. Pathol. 113, 160e162. Varnier, A.L., Sanchez, L., Vatsa, P., Boudesocque, L., Garcia-Brugger, A., ment, C., Rabenoelina, F., Sorokin, A., Renault, J.H., Kauffmann, S., Pugin, A., Cle Baillieul, F., Dorey, S., 2009. Bacterial rhamnolipids are novel MAMPs conferring resistance to Botrytis cinerea in grapevine. Plant Cell Environ. 32, 178e193. Vega, L.M., Barboza-Corona, J.E., Aguilar-Uscanga, M.G., Ramírez-Lepe, M., 2006. Purification and characterization of an exochitinase from Bacillus thuringiensis subsp. aizawaiandits action against phytopathogenic fungi. Can. J. Microbiol. 52, 651e657. Velho, R.V., Medina, L.F., Segalin, J., Brandelli, A., 2011. Production of lipopeptides among Bacillus strains showing growth inhibition of phytopathogenic fungi. Folia Microbiol. (Praha) 56, 297e303. Wang, S.-L., Shih, I.-L., Liang, T.-W., Wang, C.-H., 2002. Purification and characterization of two antifungal chitinases extracellularly produced by Bacillus amyloliquefaciens V656 in a shrimp and Crab shell powder medium. J. Agr. Food Chem. 50, 2241e2248. Wei, J.Z., Hale, K., Carta, L., Platzer, E., Wong, C., Fang, S.C., Aroian, R.V., 2003. Bacillus thuringiensis crystal proteins that target nematodes. Proc. Natl. Acad. Sci. U. S. A. 100, 2760e2765.  Co ^ te , J.-C., 2005. Development of a Bacillus thuringiensisWellman-Desbiens, E., Based assay on Lygus hesperus. J. Econ. Entomol. 98, 1469e1479. Wu, Y., Lei, C.-F., Yi, D., Liu, P.-M., Gao, M.Y., 2011. Novel Bacillus thuringiensis dendotoxin active against Locusta migratoria manilensis. Appl. Environ. Microbiol. 77, 3227e3233. Xia, Y., Xie, S., Ma, X., Wu, H., Wang, X., Gao, X., 2011. The purL gene of Bacillus subtilis is associated with nematicidal activity. FEMS Microbiol. Lett. 322, 99e107. Yan, F., Xu, S., Chen, Y., Zheng, X., 2014. Effect of rhamnolipids on Rhodotorula glutinis biocontrol of Alternaria alternata infection in cherry tomato fruit. Post. Biol. Technol. 97, 32e35. Yan, L., Jing, T., Yujun, Y., Bin, L., Hui, L., Chun, L., 2011. Biocontrol efficiency of Bacillus subtilis SL-13 and characterization of an antifungal chitinase. Biotechnol. Bioeng. Chin. J. Chem. Eng. 19, 128e134. Yu, X., Zheng, A., Zhu, J., Wang, S., Wang, L., Deng, Q., Li, S., Liu, H., Li, P., 2011. Characterization of vegetative insecticidal protein vip genes of Bacillus thuringiensis from Sichuan Basin in China. Curr. Microbiol. 62, 752e757. Yuan, J., Raza, W., Shen, Q., Huang, Q., 2012. Antifungal activity of Bacillus amyloliquefaciens NJN-6 volatile compounds against Fusarium oxysporum f. sp. cubense. Appl. Environ. Microbiol. 78, 5942e5944. Zhao, Z., Wang, Q., Wang, K., Brian, K., Liu, C., Gu, Y., 2010. Study of the antifungal activity of Bacillus vallismortis ZZ185 in vitro and identification of its antifungal components. Bioresour. Technol. 101, 292e297. Zhong, C., Ellar, D.J., Bishop, A., Johnson, C., Lin, S., Hart, E.R., 2000. Characterization of a Bacillus thuringiensis delta-endotoxin which is toxic to insects in three orders. J. Invertebr. Pathol. 76, 131e139. Zhou, T., Chen, D., Li, C., Sun, Q., Li, L., Liu, F., Shen, Q., Shen, B., 2012. Isolation and characterization of Pseudomonas brassicacearum J12 as an antagonist against Ralstonia solanacearum and identification of its antimicrobial components. Microbiol. Res. 167, 388e394. Zhou, Y., Choi, Y.-L., Sun, M., Yu, Z., 2008. Novel roles of Bacillus thuringiensis to control plant diseases. Appl. Microbiol. Biotechnol. 80, 563e572.