Analysis of Cytosine Methylation Status in Potato by Methylation-sensitive Amplified Polymorphisms under Low-temperature Stress

China is the leading producer of potatoes (Solanum tuberosum) in the world. However, low-temperature stress can severely restrict the yield and quality of potato crops in that country. We used methylation-sensitive amplified polymorphisms (MSAPs) to analyze how such stress might alter the status of cytosine methylation in potato cultivar 'Atlantic'. Over 2400 loci were identified and assessed for DNA methylation in chilling-treated and control plants. The level of cytosine methylation increased from 37.71% to 56.51% after 48 h of treatment but then decreased to 42.14% after 60 h of chilling. Stress-induced changes in the banding patterns of DNA methylation primarily resulted from full methylation of CG (internal cytosine of 5'-CCGG-3') on double DNA strands. We sequenced 78 polymorphic DNA fragments and blasted them against NCBI. Expression patterns of 4 genes were then assessed via semi-quantitative RT-PCR. The expression patterns of genes related to chilling stress appeared to be regulated by the methylation or demethylation status in potato.