Epigenetic responses to drought stress in rice (Oryza sativa L.)

• Published in: Physiology and molecular biology of plants 2013-07, Vol.19 (3), p.379-387
• Main Authors: Gayacharan, Joel, A. John
• Format: Article
• Language: English
• Subjects: Biological and Medical Physics; Biomedical and Life Sciences; Biophysics; Cell Biology; Life Sciences; Plant Physiology; Plant Sciences; Research Article
• ISSN: 0971-5894; 0974-0430
• DOI: 10.1007/s12298-013-0176-4

Cytosine methylation polymorphism plays a key role in gene regulation, mainly in expression of genes in crop plants. The differential expression of cytosine methylation over drought stress response was analyzed in rice using drought susceptible but agronomically superior lines IR 20 and CO 43, and drought tolerant genotypes PL and PMK 3 and their F 1 hybrids. The parents and hybrids were subjected to two moisture regimes viz., one under drought condition and another under control condition. The cytosine methylation polymorphism in genomic DNA was quantified under both the conditions at the reproductive stage of the plant using the M ethylation S ensitive A mplified P olymorphism (MSAP) technique devised by Xiong et al. (261:439–446, 1999 ). The results depicted that under drought condition, hyper-methylation was predominant in the drought susceptible genotypes while drought tolerant genotypes presented hypo-methylation behavior. While imposing drought, spikelet sterility per cent was positively correlated to percentage of methylation whereas, panicle length, number of seed per panicle, panicle weight, 100 seed weight, and yield/plant were negatively correlated indicating the role of epigenetic regulation in yield attributing traits in response to drought. Thus, methylation can be considered as an important epigenetic regulatory mechanism in rice plants to adapt drought situation. From this study, we speculate that the hyper- methylation may be an indicator of drought susceptibility and the hypo-methylation for drought tolerance and this methylation polymorphism can be effectively used in drought screening program.