Published online by Cambridge University Press: 24 August 2020
DNA methylation is known to regulate gene expression when plants are exposed to abiotic stress such as drought. Therefore, insight into DNA methylation pattern would be useful for a better understanding of the expression profile of genes associated with drought adaptation. In the present study, we attempted to analyse the DNA methylation pattern at the whole-genome level and the expression of a few drought-responsive genes in rice under different regimes of soil water status, i.e. puddled, 100 and 60% field capacities (FC). The methylation-sensitive randomly amplified polymorphic DNA analysis was employed to identify DNA methylation pattern. We observed an increase in DNA methylation at 60% FC, and reduced methylation under 100% FC compared to puddled condition. The genes such as protein phosphatases (PP2C) and phenylalanine ammonia-lyase (PAL) having CpG islands in their promoter region had lower expression level under 100 and 60% FC compared to puddled conditions. Heat shock protein 70 (HSP70) and RNA helicase 25 (RH25), with no CpG islands in their promoter region, exhibited enhanced expression compared to puddled plants. In rice, increased DNA methylation seems to be an important mechanism associated with drought responses, which probably regulates the methylation-sensitive gene expression. The drought-induced changes in DNA methylation would contribute for epigenetic mechanism. The study provided evidence to argue that drought-induced increased methylation might be one of the major mechanisms associated with acclimation responses in field crops like rice.