Effect of 5-azacytidine induced DNA demethylation on abiotic stress tolerance in Arabidopsis thaliana

The effect of 5-azacytidine (5A)-induced DNA hypomethylation on the growth and abiotic stress tolerance of Arabidopsis thaliana were analysed. Growth analysis revealed that aqueous solutions of 5A added to the soil did not affect the fresh and dry biomass accumulation but led to a higher percentage of flowering A. thaliana plants after four weeks of cultivation. The 5A treatment considerably lowered survival rates of Arabidopsis plants under high soil salinity, heat stress, and drought, while it did not affect the survival rates after freezing stress. 5A eliminated the stimulatory effect of the heat and drought stresses on the transcriptional levels of a number of stress-inducible genes, such as DREB1, LEA, SOS1, or RD29A. A less clear but similar trend has been detected for the effect of 5A on expression of the stress-inducible genes under salt and cold stresses. The data indicate that DNA methylation is an important mechanism regulating plant abiotic stress resistance.