Transcriptional profiling of plant embryogenesis.

Abstract

The process of embryogenesis in higher plants is a critical stage of the sporophytic life cycle, transforming the fertilised egg cell via a precise sequence of events into a multi-cellular organism. It is during embryogenesis that the body plan of the developing plant is established. Analysis of transcriptional changesembryo. This thesis demonstrates the application of laser capture micro dissection to the analysis of embryogenesis in the model plant Arabidopsis thaliana. This technique has been used in combination with DNA microarray technology to allow a global analysis of gene expression in the cotyledon, root and shoot apical meristem regions of the torpedo-stage embryo. Validation of the approach has been achieved by comparison of the ATH1 GeneChip® data obtained, with published gene expression patterns confirmed by in situ hybridisation and promoter: GUS analysis. Further validation was successfully undertaken through the creation of promoter: Gus constructs for a number of previously uncharacterised putative transcription factor genes, selected on the basis of differential expression between the cotyledon and root regions. Initial attempts to assign putative function to these genes through an analysis of T-DNA insertion lines yielded no aberrant phenotypes. Transcriptional profiling of embryogenesis from the globular-stage through to the torpedo-stage was carried out using GeneSpring, uncovering distinct spatial and temporal expression patterns, and revealing a number of genes of potential interest for further research.