The epigenome and plant development.

The epigenomic regulation of chromatin structure and genome stability is essential for the interpretation of genetic information and ultimately the determination of phenotype. High-resolution maps of plant epigenomes have been obtained through a combination of chromatin technologies and genomic tiling microarrays and through high-throughput sequencing-based approaches. The transcriptomic activity of a plant at a certain stage of development is controlled by genome-wide combinatorial interactions of epigenetic modifications. Tissue- or environment-specific epigenomes are established during plant development. Epigenomic reprogramming triggered by the activation and movement of small RNAs is important for plant gametogenesis. Genome-wide loss of DNA methylation in the endosperm and the accompanying endosperm-specific gene expression during seed development provide a genomic insight into epigenetic regulation of gene imprinting in plants. Global changes of histone modifications during plant responses to different light environments play an important regulatory role in a sophisticated light-regulated transcriptional network. Epigenomic natural variation that developed during evolution is important for phenotypic diversity and can potentially contribute to the molecular mechanisms of complex biological phenomena such as heterosis in plants.