Plant & Animal Genomes XVI Conference

January 12-16, 2008
Town & Country Convention Center
San Diego, CA

Exploring Epigenetic Variation And Its Consequences In Brassica

Graham J King , Stephen Amoah

  Rothamsted Research, Harpenden, AL5 2JQ, U.K.

The role epigenetic regulation plays in Genotype by Environment (GxE) interactions is poorly understood, although it appears to be a normal and essential mechanism for co-ordinating eukaryote genome activity. There is scope to harness epigenetic variation for crop improvement, particularly within complex crop genomes such as those comprising the Brassica 'triangle of U'.
To determine the likely consequences of changes in DNA methylation status on key crop traits, we have established a hypomethylated ‘epi-mutant population’, based on 5-Azacytidine (5-AzaC) seed treatment of the B. rapa. genotype R-O-18, which will be directly comparable with sibling EMS 'TILLING' and radiation mutant populations being developed in the lab of Lars Ostergaard (JIC, Norwich). We previously demonstrated in B. oleracea that treatment with 5-AzaC can result in heritable effects on plant stature, flowering time, inflorescence architecture and other developmental traits. In the B. rapa M1 and M2 generations we observe a range of epimutant phenotypes. These materials are valuable for detailed analysis in context of expression of genes well characterised in model and crops.
We are optimising methods to generate ‘epigenome’ maps (methylome) of the distribution of methylated cytosines (5mC) at different levels of resolution. This includes screening of potential target regions using high-resolution melt (HRM) analysis, and optimising immunoprecipitation and direct methods for screening of macro and oligo genomic tiling arrays. We have initiated a programme to carry out systematic analysis of the Brassica epi-genome using a combination of predictive bioinformatic and experimental approaches.