紫芽茶树类黄酮生物合成关键酶基因表达与总儿茶素、花青素含量相关性分析

Correlation Analysis between Total Catechins(or Anthocyanins) and Expression Levels of Genes Involved in Flavonoids Biosynthesis in Tea Plant with Purple Leaf

儿茶素类化合物与花青素均由类黄酮代谢途径合成,紫芽茶中富含花青素。为探明紫芽茶树中类黄酮生物合成代谢流的情况,本试验以来源于湄潭苔茶后代的1株紫色芽叶茶树和1株绿色芽叶茶树为材料,测定芽下第一叶、第二叶和第三叶的叶色、儿茶素类组分和花青素总量,分析了类黄酮生物合成相关的基因表达情况及基因表达量同总儿茶素、花青素累积量之间的相关性。结果表明,紫芽茶树中各叶位中花青素含量均显著高于对照绿芽茶树,而儿茶素类总量却低于对照;类黄酮生物合成关键酶(PAL、CHS、CHI、F3H、DFR、ANS、ANR1、ANR2、F3’H和F3’5’H)基因均呈现上调趋势。紫色芽叶中的总儿茶素与花青素,同各相关基因(LAR除外)表达水平的相关性都较高,且二者相关系数差异不大。绿色芽叶中的总儿茶素与各基因(LAR、F3’H除外)表达的相关系数,明显高于花青素同各基因表达的相关系数。

Flavan-3-ols（aka catechins） and Anthocyanins found in large amounts in tea plant with purple leaf are synthesized through flavonoids metobolic pathway. To investigate the metobolic flux of flavanoids biosynthetic pathway in tea plant with purple leaf, we employed a tea plant with purple leaf and a tea plant with green leaf both from Mei-Tan-Tai-Cha, to examine the expression profiles of related genes involved in flavonoids biosynthesis intensively and determine the concentrations of catechins and anthocynins. The correlation between total catechins（or anthocyanin） and the expression levels of related genes were analyzed. The results indicated that the expression levels of related genes（PAL, CHS, CHI, F3 H, DFR, ANS, ANR1, ANR2, F3＇H, and F3＇5＇H） were up-regulated in purple leaves as compared with those in the green leaves. The purple leaf also had higher concentration of anthocyanins than the green leaf, while the green leaf was richer in total catechins. In purple leaves, the expression levels of related genes（except LAR） were highly correlated with both concentrations of total catechins（r = 0.84–0.99） and anthocyanins（r = 0.72–1.00）. In contrast, there was only a high correlation between the expression levels of related genes（except LAR and F3＇H） and the concentration of total catechines（r = 0.64–0.77） in green leaves.