DNA Methylation Changes in Response to Sulfur Dioxide Stress in Arabidopsis Plants

Sulfur dioxide (SO2) exposure causes alterations of DNA cytosine methylation in Arabidopsis genome. Analysis of methylation-sensitive amplified polymorphism (MSAP) revealed that SO2 induced methylation changes of cytosine in CCGG sites, in which hypermethylation is more than hypomethylation. Bisulfite sequencing showed that the methyaltion levels of cytosine in promoter regions of Arabidopsis genes encoding 1-aminocyclopropane-1-carboxylic acid synthase 6 and nitrilase 2 decreased accompanying with enhanced transcript levels. The global genome hypermethylation and locus-specific hypomethylation in Arabidopsis cells, which contribute to genome stability and gene regulation, can be considered as a very important regulatory mechanism for plants adaption to environmental stress.