Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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SiRNA profiling of Arabidopis leaf from antisense SPH1 plants vs wild type

ABSTRACT: Arabidopsis genome sequencing has revealed the presence of at least three extensive gene families that may encode protein ligands. One of these, the SPH (S-protein homologue) family, was identified as a direct result of our studies on self-incompatibility in Papaver. The Arabidopsis SPH gene family consists of 81 members. We have initiated experimental work on a subset of these. RT-PCR studies indicate that many, if not all, SPH genes are expressed. Each SPH gene encodes an N-terminal signal peptide sequence and thus SPH proteins are likely to be secreted. Until recently none of the genes in this family had known function. However we have evidence that one member of the family, SPH1 is involved in leaf vascular development. In order to determine the function of SPH1, Arabidopsis plants were transformed with an SPH1 antisense construct. Analysis of the mutant phenotype shows that whilst plants appear as wt until principal growth stage 1.04, they subsequently show severe morphological defects. Plants are severely dwarfed with twisted rosette leaves at ~ 30% wt length and width as well as shortened inflorescence stem. Closer examination revealed aberrant leaf vasculature and severe reduction in expansion of parenchyma cells surrounding the primary leaf vein. We have conducted preliminary immunolocalisation studies with antibody raised to SPH1. These suggest that SPH1 protein is secreted by cells within the developing vasculature of the immature leaf (leaves<6mm in length). The data that we have so far obtained leads us to believe that SPH1 protein acts as a signalling molecule during early leaf development. As SPH1 is likely to be a signalling protein it is assumed that its interaction with a cognate receptor results in initiation of developmental processes within leaf tissue. The purpose of the experiment is to determine the network of genes within the normally developing rosette leaf whose expression is altered by SPH1. This will be accomplished by comparing transcriptional levels in rosette leaves of antisense-SPH1 plants with wt plants. We propose to make target RNA from rosette leaves taken from plants at principal stage 1.05 (immediately after initial appearance of developmental abnormality) and from plants at principal stage 1.14 (where gross changes are apparent). We propose to use replicate slides for each hybridisation, i.e. 2 hybridised to RNA from wt leaves at 1.05, 2 antisense at 1.05, 2 wt at 1.14 and 2 antisense at 1.14. Experiment Overall Design: Number of plants pooled:40

ORGANISM(S): Arabidopsis thaliana

SUBMITTER: Nottingham Arabidopsis Stock Centre (NASC)

PROVIDER: E-GEOD-6179 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Arabidopsis genome sequencing has revealed the presence of at least three extensive gene families that may encode protein ligands. One of these, the SPH (S-protein homologue) family, was identified as a direct result of our studies on self-incompatibility in Papaver. The Arabidopsis SPH gene family consists of 81 members. We have initiated experimental work on a subset of these. RT-PCR studies indicate that many, if not all, SPH genes are expressed. Each SPH gene encodes an N-terminal signal peptide sequence and thus SPH proteins are likely to be secreted. Until recently none of the genes in this family had known function. However we have evidence that one member of the family, SPH1 is involved in leaf vascular development. In order to determine the function of SPH1, Arabidopsis plants were transformed with an SPH1 antisense construct. Analysis of the mutant phenotype shows that whilst plants appear as wt until principal growth stage 1.04, they subsequently show severe morphological defects. Plants are severely dwarfed with twisted rosette leaves at ~ 30% wt length and width as well as shortened inflorescence stem. Closer examination revealed aberrant leaf vasculature and severe reduction in expansion of parenchyma cells surrounding the primary leaf vein. We have conducted preliminary immunolocalisation studies with antibody raised to SPH1. These suggest that SPH1 protein is secreted by cells within the developing vasculature of the immature leaf (leaves<6mm in length). The data that we have so far obtained leads us to believe that SPH1 protein acts as a signalling molecule during early leaf development. As SPH1 is likely to be a signalling protein it is assumed that its interaction with a cognate receptor results in initiation of developmental processes within leaf tissue. The purpose of the experiment is to determine the network of genes within the normally developing rosette leaf whose expression is altered by SPH1. This will be accomplished by comparing transcriptional levels in rosette leaves of antisense-SPH1 plants with wt plants. We propose to make target RNA from rosette leaves taken from plants at principal stage 1.05 (immediately after initial appearance of developmental abnormality) and from plants at principal stage 1.14 (where gross changes are apparent). We propose to use replicate slides for each hybridisation, i.e. 2 hybridised to RNA from wt leaves at 1.05, 2 antisense at 1.05, 2 wt at 1.14 and 2 antisense at 1.14. Keywords: genetic_modification_design

Project description:The aim of this study is to identify Arabidopsis genes whose expression is altered by aphid feeding. An understanding of the plant aphid interaction at the level of the plant transcriptome will 1) consolidate current areas of investigation focused on the phloem composition (the aphid diet), 2) open up areas of plant aphid interactions for ourselves and other workers, 3) Contribute to understanding the use of new molecular technologies in an environmental context and 4) contribute to existing and development of novel control strategies.Our Arabidopsis/Myzus persicae system provides a valuable model for the study because of: a) the advantages of using Arabidopsis, b) The ability to use clonal insects, c) phloem feeding aphids facilitate focus on a specific cell type, d) aphid stylectomy allows collection of pure phloem sap to monitor ?phloem phenotype?? of the plant and the insect diet, e) we have techniques to monitor the reproductive performance and feeding behaviour aphids.Our strategy has been to test the function of selected genes, particularly those regulating phloem composition (the feeding site of the aphid) based on current phloem models of phloem function. Gene choice is limited the simplicity of current models of phloem aphid interaction.We propose a simple two treatment (aphid infested vs control plants) experiment that will identify novel target genes for future analysis. Arabidopsis plants (variety Columbia) will be grown in 16/8 light/dark in temperature controlled growth rooms. At growth stage 3.90, when rosette growth is complete, 10 clonal adult Myzus persicae will be caged in clip cages on the two largest leaves on each plant. Control plants will be treated identically except that the cages will be empty. Leaves will be harvested 8 h after infestation. This time point is selected as we know that 90% of aphids are plugged into the sieve element within 2h and that a 6h lag phase has period has previously been used when examining gene expression affected by wounding. In subsequent experiments we will examine time courses of expression of relevant genes using other approaches. Pooling two leaves from each of ten plants will generate the RNA sample, ensuring that expression signals are representative of the population of plants. Experiment Overall Design: Number of plants pooled:10

Project description:This proposal is aimed at providing transcriptome data to underpin a long-term joint research programme of Steve Smith and Alison Smith. We are jointly studying starch synthesis and breakdown in Arabidopsis leaves, and individually studying other enzymes of carbohydrate metabolism (eg. sucrose synthases, invertases, sugar transporters). Collectively these enzymes are encoded by up to 100 known genes, but there are many others of relevance to our studies. For several years we have employed a defined set of growth conditions for this work (resulting in numerous publications). We have extensive data for changes in the amounts of starch, malto-oligosaccharides and sugars throughout the diurnal cycle in these plants, and we intend to quantitate numerous key enzymes. We now wish to profile changes in transcripts in these plants, so that this information can be correlated with changes in the amounts of key enzymes and metabolites. Analysis of the data sets will help us to relate the synthesis of certain enzymes to particular metabolic functions, and also to help identify genes encoding novel proteins involved in carbohydrate metabolism. Current research is aimed at discovering such novel proteins using proteomics approaches (BBSRC Grant: _Discovery and Functional Analysis of the Starch Proteome_). While the growth conditions (12h photoperiod, 150 umol/m2/s, 20C) and ecotype (Col-0) are specifically tailored to our experiments, they will be of value to the wider community, and could form the basis for collaborative studies with other groups. The experiment has involved sampling leaves at eleven different time points as follows: 0, 1, 2, 4, 8, 12, 13, 14, 16, 20, and 24 h (where time 0 is the onset of dark and 12 h is the onset of light). The 24 h time point is a repeat of 0 h. This sequence provides relatively more samples immediately after the light-dark transitions, when changes in metabolism are most pronounced. Plants were grown in a controlled environment chamber under defined conditions, and selected for harvest according to a random number generator. Three fully expanded leaves were harvested from each of 20 plants for each sample. Leaves were frozen at -80 C and a portion saved for metabolite and enzyme assays while RNA was isolated from the remainder. The RNA has been purified and is ready to send to Nottingham. Experiment Overall Design: Number of plants pooled:20 Experiment Overall Design: Biological replicates: 2

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SiRNA profiling of Arabidopis leaf from antisense SPH1 plants vs wild type

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