Epigenetics of Common Bean Drought Stress Response: An Integrated Study of Chromatin Marks, Transcription and Stress Signaling

Drought stress is one of the major threats to plants in the context of global climate change. Plants have to respond promptly in order to maintain their homeostasis. The external signal perceived by the plants during stress is transduced through a particular signaling pathway via specific signaling receptors, which ultimately results in rapid and specific modulation of the plant transcriptome. There are many reports suggesting that post-translational histone modifications are altered by environmental stress and could be a primary target for plant drought stress responses. But so far, clear relationships between drought stress-dependent signal, chromatin modification, and transcriptional response in legumes such as common bean (Phaseolus vulgaris L.) are not available. In the present investigation, common bean cultivar ‘Sierra’ was subjected to various drought stress including mild (75% water capacity), moderate (50% water capacity), severe (35% water capacity) and combinations of the three stress. Plants were subjected to repeated dehydration and rehydration for five days in order to investigate drought stress memory. Reverse transcription PCR amplification of the PvLEA transcript provides an indication for dehydration and rehydration status of plants. Interaction of histone marks such as H4K12ac, H3K9ac, H3K9me2 and H3K4me3 with transcriptional and drought stress signaling responses in common bean will be studied using ChIP-PCR. Interaction of chromatin modification with transcriptional and stress signaling responses in plants will help us better understand the important area of environmental epigenetics.