Epigenomic Profiling to Gain Insight in Heterosis in Rice

Heterosis defines increased vigor in hybrid progeny as compared to their inbred parents. Its molecular basis is poorly understood, although it is clear that genetic differences play a role in the phenotype observed. We hypothesize that mis-regulation of transcription leads to enhanced growth associated with hybrid vigor. The dynamic modification of DNA and histones plays a key role in transcriptional regulation through altering the packaging of DNA and modifying the nucleosome surface. These chromatin states, also referred to as the epigenome, are distinctive for different tissues, developmental stages, and disease states and can also be altered by environmental influences. This study is aimed at investigating the possible role of tri-methylation of histone H3 lysine 27 (H3K27me3) in heterosis. Proper regulation of H3K27me3 through the Polycomb-repressive complex (PRC) plays a vital role in development in both, animals and plants. Using ChIP-seq (ChIP followed by high-throughput sequencing), epigenomic profiles for H3K27me3 and H3K4me3 in four parental and 36 hybrid progeny have been obtained. Results will be presented and possible role of H3K27me3 during development will be discussed.