- Email: [email protected]
Lexical botany
406
News & Comment
herbarium specimens are old, extremely fragile and easily damaged by handling. In an attempt to prevent further damage to the invaluable specimens in its care, the Moscow State University has made a CD of its Linnean herbarium, featuring high-resolution scanned images of the specimens. Whether or not such images will fully substitute for inspection of the herbarium sheet, at least they should be spared the ravages of the herbarium beetle. (http://www.alphagalileo.org/ ReadNotice.cfm?ReleaseID=6512) NC
TRENDS in Plant Science Vol.6 No.9 September 2001
Lexical botany The US president, George W. Bush, recently told a NATO news conference in Brussels, ‘I hope the notion of a unilateral approach died in some people’s minds here today.’ He further went on to say that ‘unilateralists don’t come around the table to listen to others.’ According to William Safire, a linguist at the New York Times (1 July 2001, Sunday Magazine, p. 26), the word unilateralist was not always politically repulsive. The word originated from botany and
described a cluster of flowers growing on one side of the stalk. It became part of politicians’ speech half a century ago when Arthur Schlesinger wrote, ‘Unilateralism, to coin one more gobbledygook term, has become the new isolationism.’ TS
Nigel Chaffey [email protected] Trevor Stokes [email protected]
Letters
Plant response to bruchins Bruchins, which are lipids extracted from the pea weevil (Bruchus pisorum), can stimulate cell division and callus development on pods of Pisum sativum plants carrying the dominant gene Np (Refs 1,2). This neoplastic-like response can be accompanied by tissue browning around the application site. Such changes resemble classic defense responses2, and have in this case been shown to protect the plant from the insect at least partially by making it more difficult for larvae to invade the pod1. We believe that linking these events with galling by insects as Edward Farmer suggests3, is premature. First, bruchins do not elicit gall development; they merely stimulate cell proliferation. Although all galls involve increased cell division4,5 and most microbial galls are relatively unstructured, insect galls are never simple enough to be described merely as ‘neoplasms’. Even the simplest insect galls exhibit considerable organization and differentiation4,5, usually including at least one specialized tissue on which the galling insect feeds4. Second, the plant response to bruchins can be characterized satisfactorily as defensive; bruchins elicit at least partial resistance to the insect1,2 in a manner seen in other systems6. The modern concept of insect galls is that they are not plant defenses but are modifications of plant development under the direction of the insect, formed for the insect’s benefit7. Third, bruchins are only one of many possible mechanisms by which insects http://plants.trends.com
could stimulate cell division. Although we certainly would agree that characterizing bruchin-directed plant gene expression ought to be pursued, insects and their galls are known to produce, contain, or alter auxins, cytokinins, proteins and other interacting hormones and signals8–10, any of which could influence plant cell division as well as development. Sorting through and identifying the signal or signals that are actually provided by the insect to elicit a gall remains a complex problem. It is not clear that the discovery of bruchins that do not elicit galls, provides a solution. Understanding gall elicitation by insects requires detailed study of the dynamic molecular and cytological mechanisms involved in the development of these aberrant plant structures11. Indeed, the optimal approach might be similar to the one proposed elsewhere by Farmer and colleagues12 for the study of plant responses to herbivory. But, to date, there are more potential signals from insects than there are well characterized molecular and developmental events in the plant. Although the discovery of bruchins contributes a piece to the puzzle of gall development, it is important to remember that insect galls comprise far more than neoplastic growth, and the key to solving the puzzle lies in learning how – and which – insect signals produce their fascinating complexity. Jack C. Schultz Dept of Entomology, Ecological and Molecular Plant Physiology Program, 1 Pesticide Research Laboratory, Penn State University, University Park, PA 16802, USA. e-mail: [email protected]
Karsten Schonrogge Centre of Ecology and Hydrology, CEH Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset, UK DT2 8ZD. Conrad Paul Lichtenstein School of Biological Sciences, Queen Mary, University of London, London, UK E1 4NS. References 1 Doss, R.P. et al. (1995) Response of Np mutant of pea (Pisum sativum L.) to pea weevil (Bruchus pisorum L.) oviposition and extracts. J. Chem. Ecol. 21, 97–106 2 Doss, R.P. et al. (2000) Bruchins: insect-derived plant regulators that stimulate neoplasm formation. Proc. Natl. Acad. Sci. U. S. A. 97, 6218–6223 3 Farmer, E.E. (2000) Potent mitogenic lipids from gall-inducing insects. Trends Plant Sci. 5, 359–360 4 Shorthouse, J.D. and Rohrfritsch, O.E., eds (1992) Biology of Insect-Induced Galls, Oxford University Press 5 Bayer, M.H. et al. (1994) Abnormal growth processes in plants and animals: a comparison. In vivo 8, 3–16 6 Fernandes, G.W. (1998) Hypersensitivity as a phenotypic basis of plant induced resistance against a galling insect (Diptera: Cecidomyiidae). Environ. Entomol. 27, 260–267 7 Price, P.W. et al. (1987) Adaptive nature of insect galls. Environ. Entomol. 16, 15–24 8 Hori, K. (1992) Insect secretions and their effect on plant growth, with special reference to Hemipterans. In Biology of Insect-Induced Galls (Shorthouse, J.D. and Rohfritsch, O.E., eds), pp. 157–170, Oxford University Press 9 White, B.N. et al. (1975) An analysis of five serine transfer ribonucleic acids from Drosophila. J. Biol. Chem. 250, 515–521 10 Hovanitz, W. (1959) Insects and plant galls. Sci. Am. 201, 151–162 11 Schönrogge, K. et al. (1998) Reprogramming plant development: two approaches to study the molecular mechanism of gall formation. In The Biology of Gall-Inducing Arthropods (Csóka, G. et al., eds), pp. 153–160, Gen. Tech. Rep. NC–199, US Dept of Agriculture, Forest Service 12 Reymond, P. et al. (2000) Differential gene expression in response to mechanical wounding and insect feeding in Arabidopsis. Plant Cell 12, 707–719
1360-1385/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S1360-1385(01)02041-6
News & Comment
herbarium specimens are old, extremely fragile and easily damaged by handling. In an attempt to prevent further damage to the invaluable specimens in its care, the Moscow State University has made a CD of its Linnean herbarium, featuring high-resolution scanned images of the specimens. Whether or not such images will fully substitute for inspection of the herbarium sheet, at least they should be spared the ravages of the herbarium beetle. (http://www.alphagalileo.org/ ReadNotice.cfm?ReleaseID=6512) NC
TRENDS in Plant Science Vol.6 No.9 September 2001
Lexical botany The US president, George W. Bush, recently told a NATO news conference in Brussels, ‘I hope the notion of a unilateral approach died in some people’s minds here today.’ He further went on to say that ‘unilateralists don’t come around the table to listen to others.’ According to William Safire, a linguist at the New York Times (1 July 2001, Sunday Magazine, p. 26), the word unilateralist was not always politically repulsive. The word originated from botany and
described a cluster of flowers growing on one side of the stalk. It became part of politicians’ speech half a century ago when Arthur Schlesinger wrote, ‘Unilateralism, to coin one more gobbledygook term, has become the new isolationism.’ TS
Nigel Chaffey [email protected] Trevor Stokes [email protected]
Letters
Plant response to bruchins Bruchins, which are lipids extracted from the pea weevil (Bruchus pisorum), can stimulate cell division and callus development on pods of Pisum sativum plants carrying the dominant gene Np (Refs 1,2). This neoplastic-like response can be accompanied by tissue browning around the application site. Such changes resemble classic defense responses2, and have in this case been shown to protect the plant from the insect at least partially by making it more difficult for larvae to invade the pod1. We believe that linking these events with galling by insects as Edward Farmer suggests3, is premature. First, bruchins do not elicit gall development; they merely stimulate cell proliferation. Although all galls involve increased cell division4,5 and most microbial galls are relatively unstructured, insect galls are never simple enough to be described merely as ‘neoplasms’. Even the simplest insect galls exhibit considerable organization and differentiation4,5, usually including at least one specialized tissue on which the galling insect feeds4. Second, the plant response to bruchins can be characterized satisfactorily as defensive; bruchins elicit at least partial resistance to the insect1,2 in a manner seen in other systems6. The modern concept of insect galls is that they are not plant defenses but are modifications of plant development under the direction of the insect, formed for the insect’s benefit7. Third, bruchins are only one of many possible mechanisms by which insects http://plants.trends.com
could stimulate cell division. Although we certainly would agree that characterizing bruchin-directed plant gene expression ought to be pursued, insects and their galls are known to produce, contain, or alter auxins, cytokinins, proteins and other interacting hormones and signals8–10, any of which could influence plant cell division as well as development. Sorting through and identifying the signal or signals that are actually provided by the insect to elicit a gall remains a complex problem. It is not clear that the discovery of bruchins that do not elicit galls, provides a solution. Understanding gall elicitation by insects requires detailed study of the dynamic molecular and cytological mechanisms involved in the development of these aberrant plant structures11. Indeed, the optimal approach might be similar to the one proposed elsewhere by Farmer and colleagues12 for the study of plant responses to herbivory. But, to date, there are more potential signals from insects than there are well characterized molecular and developmental events in the plant. Although the discovery of bruchins contributes a piece to the puzzle of gall development, it is important to remember that insect galls comprise far more than neoplastic growth, and the key to solving the puzzle lies in learning how – and which – insect signals produce their fascinating complexity. Jack C. Schultz Dept of Entomology, Ecological and Molecular Plant Physiology Program, 1 Pesticide Research Laboratory, Penn State University, University Park, PA 16802, USA. e-mail: [email protected]
Karsten Schonrogge Centre of Ecology and Hydrology, CEH Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset, UK DT2 8ZD. Conrad Paul Lichtenstein School of Biological Sciences, Queen Mary, University of London, London, UK E1 4NS. References 1 Doss, R.P. et al. (1995) Response of Np mutant of pea (Pisum sativum L.) to pea weevil (Bruchus pisorum L.) oviposition and extracts. J. Chem. Ecol. 21, 97–106 2 Doss, R.P. et al. (2000) Bruchins: insect-derived plant regulators that stimulate neoplasm formation. Proc. Natl. Acad. Sci. U. S. A. 97, 6218–6223 3 Farmer, E.E. (2000) Potent mitogenic lipids from gall-inducing insects. Trends Plant Sci. 5, 359–360 4 Shorthouse, J.D. and Rohrfritsch, O.E., eds (1992) Biology of Insect-Induced Galls, Oxford University Press 5 Bayer, M.H. et al. (1994) Abnormal growth processes in plants and animals: a comparison. In vivo 8, 3–16 6 Fernandes, G.W. (1998) Hypersensitivity as a phenotypic basis of plant induced resistance against a galling insect (Diptera: Cecidomyiidae). Environ. Entomol. 27, 260–267 7 Price, P.W. et al. (1987) Adaptive nature of insect galls. Environ. Entomol. 16, 15–24 8 Hori, K. (1992) Insect secretions and their effect on plant growth, with special reference to Hemipterans. In Biology of Insect-Induced Galls (Shorthouse, J.D. and Rohfritsch, O.E., eds), pp. 157–170, Oxford University Press 9 White, B.N. et al. (1975) An analysis of five serine transfer ribonucleic acids from Drosophila. J. Biol. Chem. 250, 515–521 10 Hovanitz, W. (1959) Insects and plant galls. Sci. Am. 201, 151–162 11 Schönrogge, K. et al. (1998) Reprogramming plant development: two approaches to study the molecular mechanism of gall formation. In The Biology of Gall-Inducing Arthropods (Csóka, G. et al., eds), pp. 153–160, Gen. Tech. Rep. NC–199, US Dept of Agriculture, Forest Service 12 Reymond, P. et al. (2000) Differential gene expression in response to mechanical wounding and insect feeding in Arabidopsis. Plant Cell 12, 707–719
1360-1385/01/$ – see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S1360-1385(01)02041-6