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Integration of leaf metabolism and physiology by the trehalose pathway
Abstracts / Comparative Biochemistry and Physiology, Part A 150 (2008) S186–S198
synthases (SSs) were identified from endosperm amyloplasts of wheat and maize during the active phases of starch deposition in the developing seeds. Analysis of protein complexes from endosperm amyloplasts indicates SSI, SSIIa and SBEII forms are components of one or more protein complexes in amyloplasts. Analysis of the maize endosperm amylose extender mutant (lacking SBEIIb) reveals novel protein complexes in this tissue. These results suggest a role for protein complexes in amylopectin biosynthesis.
S195
component in plant signalling systems, implicating phosphorylated long chain sphingoid bases such as S1P as ubiquitous messengers in plants. Current investigations include localizing the expression of SPHK1, phenotyping a SPHK1/LCBK1-knockdown mutant and measuring S1P levels. doi:10.1016/j.cbpa.2008.04.536
doi:10.1016/j.cbpa.2008.04.534 P3.36 The effects of different water supply conditions on the tomato plant and fruit growth in two tomato hybrids P3.34 Analysis of the R2R3-MYB transcription factor family identifies genes involved in stomatal function S. Lindsay (University of Bristol); L. Hunt (University of Sheffield); J. Gray (University of Sheffield); A. Hetherington (University of Bristol) The R2R3-MYB family of transcription factors regulates a range of genes throughout the life cycle of plants which are involved in the control of processes such as secondary metabolite synthesis, gamete development and stomatal function and development. Several R2R3MYB family transcription factors, MYB60, MYB61, MYB88 and MYB124 have previously been shown to be involved in light induced stomatal opening, dark induced stomatal closure and stomatal development respectively. We have undertaken a non-invasive, high-throughput analysis of many members of the R2R3-MYB gene family using a combination of bioinformatics and infrared thermal imaging. We have identified several new R2R3-MYB family members that appear to be involved in the control of stomatal function and stomatal development. Our latest results will be presented.
S. Savic (Faculty of Agriculture, University of Belgrade) The effects of regulated deficit irrigation (RDI) and partial rootzone drying (PRD) on plant and fruit growth of two tomato genotypes (Lycopersicon esculentum L., cv. Sunpak and Astona) were investigated in growth chamber conditions. The RDI treatment was 50% of water given to fully irrigated (FI) plants, although the PRD treatment was 50% of water of FI plants applied to one half of the root system while the other half dried down, with irrigation shifted when soil water content of the dry side decreased for 15% to 20%. Results showed that RDI and PRD had reducing effects on plant and fruit growth rate and duration of elongation phase in fruit cells of exocorp tissue and, consequently the fruit diameter and yield were reduced. Key words: Tomato, Partial root drying, Regulated deficit irrigation, Plant and fruit growth. doi:10.1016/j.cbpa.2008.04.537
doi:10.1016/j.cbpa.2008.04.535
P3.37 Integration of leaf metabolism and physiology by the trehalose pathway
P3.35 The role of sphingosine kinase in plant cell signalling
M. Paul (Rothamsted Research); D. Jhurreea (Rothamsted Research); L. Primavesi (Rothamsted Research); Y. Zhang, (Rothamsted Research); T. Sivagnanam (UCL); A. Wingler (UCL)
M. Panagopulos (University of Bristol); D. Worrall (Lancaster University); Y. Liang (University of Bristol); S. Alvarez (Virginia Commonwealth University); G. Holroyd (Lancaster University); S. Spiegel (Virginia Commonwealth University); J. Gray (University of Sheffield); A. Hetherington (University of Bristol) Sphingosine-1-phosphate (S1P) has well defined cell signalling roles in animal cells. We investigated the extent to which phosphorylated long chain sphingoid bases such as S1P are used in plant cell signalling by manipulating Arabidopsis genes capable of metabolizing these messenger molecules. Sphingosine kinase1 (SPHK1) encodes an enzyme that phosphorylates sphingosine, phytosphingosine and other sphingoid long chain bases. SPHK1-knockdown and SPHK1overexpressor mutant plants showed impaired stomatal responses to ABA and an altered rate of germination. We identified a gene encoding a putative Sphingosine-1-phosphatephosphatase (SPPASE) and found evidence that expression of SPHK1 and SPPASE were co-ordinately regulated. Interestingly another member of the SPHK gene family LCBK1 did not show altered gene expression in either of the mutant backgrounds. This prompted us to conduct a microarray analysis of the SPHK1 mutants and over nine hundred genes were found to be differentially expressed of which twenty-three have been previously implicated in stomatal function. These data establish SPHK1 as a
The trehalose pathway in plants has a function different to that of other carbohydrates-synthesising pathways. It has been proposed that trehalose 6-phosphate (T6P) functions as a signalling molecule regulating carbohydrate metabolism and possibly linking it with development. However, the mechanistic basis of such a function has not been clear. Here we present latest information on the function of T6P in plants focusing on downstream targets in seedling and leaves. doi:10.1016/j.cbpa.2008.04.538
P3.38 Role of the POLARIS peptide in Arabidopsis root development S. Mehdi (Durham University) Root growth in plants is coordinated by complex interactions between multiple hormone signalling pathways. The POLARIS (PLS) gene of Arabidopsis thaliana encodes a 36 amino acid peptide, and evidence suggests
synthases (SSs) were identified from endosperm amyloplasts of wheat and maize during the active phases of starch deposition in the developing seeds. Analysis of protein complexes from endosperm amyloplasts indicates SSI, SSIIa and SBEII forms are components of one or more protein complexes in amyloplasts. Analysis of the maize endosperm amylose extender mutant (lacking SBEIIb) reveals novel protein complexes in this tissue. These results suggest a role for protein complexes in amylopectin biosynthesis.
S195
component in plant signalling systems, implicating phosphorylated long chain sphingoid bases such as S1P as ubiquitous messengers in plants. Current investigations include localizing the expression of SPHK1, phenotyping a SPHK1/LCBK1-knockdown mutant and measuring S1P levels. doi:10.1016/j.cbpa.2008.04.536
doi:10.1016/j.cbpa.2008.04.534 P3.36 The effects of different water supply conditions on the tomato plant and fruit growth in two tomato hybrids P3.34 Analysis of the R2R3-MYB transcription factor family identifies genes involved in stomatal function S. Lindsay (University of Bristol); L. Hunt (University of Sheffield); J. Gray (University of Sheffield); A. Hetherington (University of Bristol) The R2R3-MYB family of transcription factors regulates a range of genes throughout the life cycle of plants which are involved in the control of processes such as secondary metabolite synthesis, gamete development and stomatal function and development. Several R2R3MYB family transcription factors, MYB60, MYB61, MYB88 and MYB124 have previously been shown to be involved in light induced stomatal opening, dark induced stomatal closure and stomatal development respectively. We have undertaken a non-invasive, high-throughput analysis of many members of the R2R3-MYB gene family using a combination of bioinformatics and infrared thermal imaging. We have identified several new R2R3-MYB family members that appear to be involved in the control of stomatal function and stomatal development. Our latest results will be presented.
S. Savic (Faculty of Agriculture, University of Belgrade) The effects of regulated deficit irrigation (RDI) and partial rootzone drying (PRD) on plant and fruit growth of two tomato genotypes (Lycopersicon esculentum L., cv. Sunpak and Astona) were investigated in growth chamber conditions. The RDI treatment was 50% of water given to fully irrigated (FI) plants, although the PRD treatment was 50% of water of FI plants applied to one half of the root system while the other half dried down, with irrigation shifted when soil water content of the dry side decreased for 15% to 20%. Results showed that RDI and PRD had reducing effects on plant and fruit growth rate and duration of elongation phase in fruit cells of exocorp tissue and, consequently the fruit diameter and yield were reduced. Key words: Tomato, Partial root drying, Regulated deficit irrigation, Plant and fruit growth. doi:10.1016/j.cbpa.2008.04.537
doi:10.1016/j.cbpa.2008.04.535
P3.37 Integration of leaf metabolism and physiology by the trehalose pathway
P3.35 The role of sphingosine kinase in plant cell signalling
M. Paul (Rothamsted Research); D. Jhurreea (Rothamsted Research); L. Primavesi (Rothamsted Research); Y. Zhang, (Rothamsted Research); T. Sivagnanam (UCL); A. Wingler (UCL)
M. Panagopulos (University of Bristol); D. Worrall (Lancaster University); Y. Liang (University of Bristol); S. Alvarez (Virginia Commonwealth University); G. Holroyd (Lancaster University); S. Spiegel (Virginia Commonwealth University); J. Gray (University of Sheffield); A. Hetherington (University of Bristol) Sphingosine-1-phosphate (S1P) has well defined cell signalling roles in animal cells. We investigated the extent to which phosphorylated long chain sphingoid bases such as S1P are used in plant cell signalling by manipulating Arabidopsis genes capable of metabolizing these messenger molecules. Sphingosine kinase1 (SPHK1) encodes an enzyme that phosphorylates sphingosine, phytosphingosine and other sphingoid long chain bases. SPHK1-knockdown and SPHK1overexpressor mutant plants showed impaired stomatal responses to ABA and an altered rate of germination. We identified a gene encoding a putative Sphingosine-1-phosphatephosphatase (SPPASE) and found evidence that expression of SPHK1 and SPPASE were co-ordinately regulated. Interestingly another member of the SPHK gene family LCBK1 did not show altered gene expression in either of the mutant backgrounds. This prompted us to conduct a microarray analysis of the SPHK1 mutants and over nine hundred genes were found to be differentially expressed of which twenty-three have been previously implicated in stomatal function. These data establish SPHK1 as a
The trehalose pathway in plants has a function different to that of other carbohydrates-synthesising pathways. It has been proposed that trehalose 6-phosphate (T6P) functions as a signalling molecule regulating carbohydrate metabolism and possibly linking it with development. However, the mechanistic basis of such a function has not been clear. Here we present latest information on the function of T6P in plants focusing on downstream targets in seedling and leaves. doi:10.1016/j.cbpa.2008.04.538
P3.38 Role of the POLARIS peptide in Arabidopsis root development S. Mehdi (Durham University) Root growth in plants is coordinated by complex interactions between multiple hormone signalling pathways. The POLARIS (PLS) gene of Arabidopsis thaliana encodes a 36 amino acid peptide, and evidence suggests