Genome-wide profiling of H3K27Ac and H3K27me3 in response to cold stress in Rice

Plants are constantly subjected to changing environmental conditions, which has prompted them to acquire means to cope up these environmental cues. Crop plants generally face both biotic as well as abiotic stresses which adversely affects their growth and development. Rice (Oryza sativa), a major crop plant world-wide is prone to such stress conditions at a greater scale, owing to its water-logging requirement during growth. Low temperature a major abiotic stress, adversely affects the growth and development of rice plants. The genetic and molecular mechanism of cold tolerance in rice plants has been a less explored area. The role of Epigenetics in abiotic stress tolerance is further less studied in rice plants. Histone modifications, a major epigenetic factor, involve various post-transcriptional modifications of histone N-terminal tail residues hence regulating the alterations in the chromatin structure in response to stress. The acetylation of Lys27 of Histone H3 (H3K27ac) is known to be an activating mark, facilitating transcription, as opposed to the trimethylation of the same residue (H3K27me3), which when present leads to repression of transcription. Together with various epigenetic marks, the chromatin dynamics play a vital role at various levels of stress responsive mechanism. Multiple reports have established the importance of chromatin remodelling in regulating chromatin states that affect transcription. This work focuses on capturing the early events occurring in Oryza sativa L. ssp. indica plants when subjected to cold-stress (4degree celsius for 2hours) at both the epigenetic and transcriptional levels. The epigenetic switch under study is the status of lysine27 of histone-H3 (H3K27). Correlating the enrichment-ratio of the H3K27ac Vs H3K27me3 modifications with gene expression levels may be used to design predictive models of transcriptional regulation by the H3K27 residue.