DNA methylation changes detected by methylation-sensitive amplified polymorphism in two contrasting rice genotypes under salt stress

DNA methylation,one of the most important epigenetic phenomena,plays a vital role in tuning gene expression during plant development as well as in response to environmental stimuli.In the present study,a methylation-sensitive amplified polymorphism(MSAP) analysis was performed to profile DNA methylation changes in two contrasting rice genotypes under salt stress.Consistent with visibly different phenotypes in response to salt stress,epigenetic markers classified as stable inter-cultivar DNA methylation differences were determined between salt-tolerant FL478 and salt-sensitive IR29.In addition,most tissue-specific DNA methylation loci were conserved,while many of the growth stage-dependent DNA methylation loci were dynamic between the two genotypes.Strikingly,salt stress induced a decrease in DNA methylation specifically in roots at the seedling stage that was more profound in IR29 than in the FL478.This result may indicate that demethylation of genes is an active epigenetic response to salt stress in roots at the seedling stage,and helps to further elucidate the implications of DNA methylation in crop growth and development.