Effect of Heat Stress on Isoenzyme and DNA Methylation of Different Heat-sensitive Peppers

By using heat-resisting,late-maturing purple pepper‘7036'and heat-sensitive,early-maturing green pepper‘9050',we studied the effects of heat stress on POD isozyme and DNA methylation expression.The results indicated that:(1)as for POD expression,one more band existed in treatment without heat stress in pepper‘7036',and different change tendency of POD activity existed in two peppers.(2)With the time extending,percentage of non-methylation and full-methylation increased,whereas percentage of half methylation and total methylation decreased in pepper‘7036',and only percentage of methylation in the treatment of heat stress for 7days(T_7)showed similar changing tendency in pepper‘9050',while its absolute values of full-methylation and half methylation ratio were significantly less than those of‘7036'.(3)As regards to methylation profiles of T_7 treatment,higher ratio of C type band of hypomethylation existed in pepper‘7036'and B type band of hypermethylation showed in pepper‘9050'.The results above showed that,recovery of POD activity,declining in percentage of half methylation and rising in percentage of fullmethylation rapidly,and hypomethylation were relevant to resisting heat stress in purple pepper‘7036'.