茶树类黄酮合成与积累的组织器官特异性研究

Tissue-specific biosynthesis and accumulation of flavonoids in tea plant

类黄酮是茶树的主要次生代谢产物,对决定茶叶品质及其健康功效具有重要作用。利用LC-TOF/MS、qRT-PCR等技术研究了茶树类黄酮合成积累的组织器官特异性。结果显示,茶树不同器官中,鲜叶中的酚酸、儿茶素和黄酮醇化合物种类较多且含量较高,原花青素含量低但种类多,而在根中则相反。从基因表达差异上看,从鲜叶到茎到根,4CL、CHI、F3H and F3’5’H表达依次降低。酶学实验显示,从鲜叶到茎到根,DFR/LAR和ANR酶活在鲜叶和茎中无明显差异,而在根中只检测到微弱的DFR/LAR活性。在不同发育时期鲜叶中,儿茶素含量在一叶中最高,芽其次;黄酮醇的含量在一叶和二叶中较高;花青素的含量随着鲜叶发育依次减少。qRT-PCR结果显示,PAL、C4H、CHS、F3’H、F3'5'H、DFR、LAR和ANR基因的表达与不同发育时期鲜叶中儿茶素和黄酮醇积累规律一致。酶学实验显示,随着鲜叶的发育,DFR/LAR的活性依次降低,ANR的活性呈增高趋势,它们的变化与酯型C和EGC含量趋势相吻合。

Flavonoids,as the main secondary metabolite in tea plant [Camellia sinensis（L.） O.Kuntze],shows decisive effects on the quality of tea and health functions.The tissue-specific synthesis and accumulation of flavonoids in tea plant were investigated by LC-TOF/MS and qRT-PCR.The result showed that phenolic acids,catechins,flavonols in different tissues and organs were abundant in the contents and diverse in the components,and the contents of proanthocyanidins were low.The components were rich in the leaves,while less in the roots.In term of gene expression,expression levels of 4CL,CHI,F3H and F3’5’H decreased in turn from the leaf,stem to the root.Enzymatic experiment showed there was no obvious difference in activities of DFR/LAR and ANR in the leaves and stems,while the weak activity of DFR/LAR was detected in the root.In leaves at different developmental stages,the content of catechin was the highest in the first leaf,followed by bud.The content of flavonol was high in the first and second leaf.The content of anthocyanin was reduced with the development of the leaves.The result of qRT-PCR showed that gene expression patterns of PAL,C4H,CHS,F3’H,F3＇5＇H,DFR,LAR and ANR were consistent with accumulation of catechins and flavonols in the leaves at different developmental stages.Enzymatic experiment showed that with the development of the fresh leaf,the activity of DFR/LAR reduced,in contrast,the activity of ANR increased gradually,which was consistent with trends of C and EGC accumulation.