Methylation Alternations In Oryza Sativa Induced By The Salt And Alkaline Stress

DNA methylation is a major component of the epigenetic regulation machinary in eukaryotes. Accumulating evidence in both animals and plants indicates that envrionmental stress may cause alteration in inrinsic methylation patterns.The salt and alkaline condition is a common environmental stress. Mechanisms by which plants are tolerant to this stress including the active function of specific genes and their regulation. In this study, by using two methods, methylation-sensitive ISSR and Southern blot, we found that the treatment by alkaline and salt, along or together, induces alteration in DNA methylation patterns in rice. Furthermore, the altered methylation patterns are heritable across biological generations, though both reversion (to that of wild type) and further alterations were aosl detetced. Alteration may also occur in plant progenies, which did not occur in their parent wherby the treatments applied.Several stress-related candidate genes were monitored for their expression in the treated plants by RT-PCR. Data showed that both alkaline and salt treatments have caused expressional changes in these genes, but the changing trend is not identical between the two kinds of treatments, suggesting that different responses and tolerance mechanisms may have evolved in the rice genome to cope with alkaline and salt stresses.