| DNA methylation is one of the most important epigenetic modifications, which plays a crucial role in regulating the development of plants during various biological processes in vivo. Researches have demonstrated numerous layers of DNA methylation of plant in recent decades, however, few is related with tea plant. Level of DNA methylation in various tissues, cultivars and different growth stage of shoots of tea plant has been monitored with HPLC in this study. The major results are as follows:1) DNA methylation levels are discrepant in different tissues and cultivars. DNA methylation levels are 31.5%,32.39%,36.46%,42.35% in stamen, petals, pistil, and mature leaves of cultivar ’Shui gu cha’,respectively; and they are 40.85%,35.97%.42.64%,40.27%, 25.53%, respectively in stamen, petals, pistil, mature leaves, and cotyledon of cultivar ’Jiu Keng’.2) DNA methylation levels are also differnt in tea shoots of various cultivars. The DNA methylation contents are 35.23%,35.54% in the shoots of early maturing cultivar "Wu niu zao" and ’Zhenong 139’, and 32.48%,37.71% in middle maturing cultivar ’Mao xie’ and ’Mei zhan’. while 37.92%,39.89% in late maturing cultivar ’Zhenghe dabaicha’ and ’Fujian shuixian’.3) Level of DNA methylation increases during growth of the shoots in cultivar ’Wu niu zao’,’Zhenong 139’,’Mao xie’,’Mei zhan’,’Zhenghe dabaicha’ and ’Fujian shixian’. The average levels of DNA methylation are 35.33%,35.55%,37.21% and 38.57% in stage of fish leaf,1st leaf,2nd leaf and 3rd leaf.4) DNA methylation level of the shoots is markedly affected by pruning. Level of DNA methylation is 36.31% in the summer shoots (two and a bud) of ’Mei zhan’ that was deeply pruned, and significantly higher than that was moderately pruned (34.83%). Similar trend has been observed in cultivar ’Zhenghe dabaicha’ and ’Fujian shuixian’. |
