Project description:Formation of functional pollen and successful fertilisation relies upon the spatial and temporal regulation of anther and pollen development. This process responds to environmental cues to maintain optimal fertility despite climatic changes. Arabidopsis transcription factors bHLH10,-89,-91 were previously thought to be functionally redundant in their control of male reproductive development, however here we show that they play distinct roles in the integration of light signals to maintain pollen development under different environmental conditions. Combinations of the double and triple bHLH10,-89,-91 mutants were analysed under normal (200μmol/m2/s) and low (50μmol/m2/s) light conditions to determine the impact on fertility. Transcriptomic analysis of a new conditionally sterile bhlh89,91 double mutant shows differential regulation of genes related to sexual reproduction, hormone signal transduction and lipid storage and metabolism under low-light. Here we have shown that bHLH89 and bHLH91 play a role in regulating fertility in response to light, suggesting they function in mitigating environmental variation to ensure fertility is maintained under environmental stress.
Project description:Aims We aim to use transcriptome analysis to establish on a genome-wide scale the identity and regulatory clusters of genes that specify microgametogenesis from the haploid microspore to mature functional pollen in Arabidopsis. Background Pollen as the haploid male gametophyte plays a vital role in plant fertility and crop production through the ability to deliver the male gametes in fertilisation. Despite the obvious importance for plant fertility and crop production we have a very limited understanding of the regulatory mechanisms that have evolved to specify male gametophyte development and functions and less than 150 genes have been identified that are gametophytically expressed in the anther.The availability of functional genomic resources now provides the opportunity to undertake a comprehensive approach to describing cellular development in terms of the transcriptome. This approach is particularly powerful where the complete transcriptome of a single developing cell can be analysed. The male gametophyte is a uniquely accessible cell type for such studies, enabling RNA analysis from distinct purified cell populations during development.The proposed experiments are designed to support a current application (P19208, Twell) to investigate the gametophytic transcriptome and transcription factor networks. The results obtained will extend our knowledge of the contribution of haploid gene expression to anther development and will be used directly to extend BBSRC funded work (P15086, Wilson) to investigate the role and targets the MALE STERILE 1 gene (MS1). In particular the data will be used in collaboration to extract haploid gene expression from datasets of transcriptome analysis of staged flower buds of wild type (Ler) and ms1. This work will also complement BBSRC funded work on sporogenesis (G13338, Dickinson and Scott) and meiosis (G15941, Franklin and Jones) that are focussed on earlier steps in anther development. Biological material and methods. Isolated microspores and pollen at 4 different developmental stages will be analysed. We will isolate spores from developmentally staged buds of Ler grown under defined growth conditions. Buds from several batches of 100 plants will be rapidly sorted into 4 groups according to developmental age, uninucleate microspores (UM), bicellular pollen (BP) tricellular pollen (TP) and mature pollen. Spores will be released by gentle mechanical tissue disruption and purified by filtration and purification of spores. We are confident that our spore isolation procedures are rigorous since we could not detect even trace expression of highly abundant sporophytic transcripts such RbcS and Cab transcripts in microarray data from pollen RNA. Keywords: development_or_differentiation_design
Project description:Aims We aim to use transcriptome analysis to establish on a genome-wide scale the identity and regulatory clusters of genes that specify microgametogenesis from the haploid microspore to mature functional pollen in Arabidopsis. Background Pollen as the haploid male gametophyte plays a vital role in plant fertility and crop production through the ability to deliver the male gametes in fertilisation. Despite the obvious importance for plant fertility and crop production we have a very limited understanding of the regulatory mechanisms that have evolved to specify male gametophyte development and functions and less than 150 genes have been identified that are gametophytically expressed in the anther.The availability of functional genomic resources now provides the opportunity to undertake a comprehensive approach to describing cellular development in terms of the transcriptome. This approach is particularly powerful where the complete transcriptome of a single developing cell can be analysed. The male gametophyte is a uniquely accessible cell type for such studies, enabling RNA analysis from distinct purified cell populations during development.The proposed experiments are designed to support a current application (P19208, Twell) to investigate the gametophytic transcriptome and transcription factor networks. The results obtained will extend our knowledge of the contribution of haploid gene expression to anther development and will be used directly to extend BBSRC funded work (P15086, Wilson) to investigate the role and targets the MALE STERILE 1 gene (MS1). In particular the data will be used in collaboration to extract haploid gene expression from datasets of transcriptome analysis of staged flower buds of wild type (Ler) and ms1. This work will also complement BBSRC funded work on sporogenesis (G13338, Dickinson and Scott) and meiosis (G15941, Franklin and Jones) that are focussed on earlier steps in anther development. Biological material and methods. Isolated microspores and pollen at 4 different developmental stages will be analysed. We will isolate spores from developmentally staged buds of Ler grown under defined growth conditions. Buds from several batches of 100 plants will be rapidly sorted into 4 groups according to developmental age, uninucleate microspores (UM), bicellular pollen (BP) tricellular pollen (TP) and mature pollen. Spores will be released by gentle mechanical tissue disruption and purified by filtration and purification of spores. We are confident that our spore isolation procedures are rigorous since we could not detect even trace expression of highly abundant sporophytic transcripts such RbcS and Cab transcripts in microarray data from pollen RNA. Experiment Overall Design: Number of plants pooled:over 100
Project description:Small RNA diversity and function has been widely characterized in various tissues of the sporophytic generation of the angiosperm model Arabidopsis thaliana. In contrast, there is limited knowledge about small RNA diversity and their roles in developing male gametophytes. We thus carried out small RNA sequencing on RNA isolated from four stages of developing Arabidopsis thaliana pollen. Spores from 4 stages of pollen development (UNM: Uninucleate microspore M-bM-^@M-^S BCP: Bicellular pollen M-bM-^@M-^S TCP: Tricellular pollen M-bM-^@M-^S MP: Mature pollen) were isolated using a percoll gradient-based method (Honys and Twell, 2004) and the small RNA fraction for each sample was isolated and sequenced by Illumina technology. Reference: Honys, D. and Twell, D. (2004) Transcriptome analysis of haploid male gametophyte development in Arabidopsis. Genome Biol. 5/11/R85.