Cytosine methylation levels in the genome of Stellaria longipes

Environment-induced alteration of DNA methylation levels was investigated i n Stellaria longipes (Caryophyllaceae). Total cytosine methylation levels w ere measured using HPLC in 6 genets representing two ecotypes (alpine and p rairie) grown in short day photoperiod and cold temperature (SDC) and long day photoperiod and warm temperature (LDW) conditions. The levels of methyl ated cytosine were 16.54-22.20% among the three genets from the alpine and 12.62-24.70% in the three prairie genets when they were grown in SDC condit ions. After the plants were moved to the LDW conditions, all of the three g enets from the alpine showed decreasing levels of DNA methylation up to 6 d ays of growing in LDW. When the plants continued to grow in LDW for 10 days the average methylation level in the prairie genotypes showed no significa nt change. Cytosine methylation level Was also detected in HpaII and Sau3AI restriction sites using the coupled restriction enzyme digestion and rando m amplification (CRED-RA) procedure, in which 15 random primers were used. Fifty per cent of the amplified bands with either or both of these two rest riction sites were identified as being methylated in an alpine genotype (1C ) and approximately 66% were found to be methylated in a prairie genotype ( 7C). It was observed that the change in growing conditions from SDC to LDW induced a decrease of methylation levels in HpaII sites.