蔗糖对茶树儿茶素生物合成的影响

Effect of sucrose on catechins biosynthesis in Camellia sinensis(L.) O. Kuntze

儿茶素是茶树重要的次生代谢产物,也是茶叶的重要功能物质,具有多种药理活性。因此正确评价茶叶及其制品中儿茶素含量,了解儿茶素生物合成及其调控手段具有重要的意义。利用香草醛盐酸比色法、HPLC等方法,研究蔗糖诱导子处理对茶儿茶素生物合成的影响,并通过qRT-PCR技术分析蔗糖处理对茶树儿茶素生物合成过程中基因表达的影响。结果显示,无论是茶树愈伤组织还是茶树幼苗经蔗糖处理后其儿茶素含量及组分都有所增加,但是高浓度的蔗糖会抑制茶树愈伤组织的生长,特别是在液体培养的早期添加蔗糖。添加适当浓度的蔗糖能增加茶树愈伤组织中非酯型儿茶素C和EC的含量;蔗糖处理后茶树幼苗中非酯型儿茶素EGC和EC含量明显上升,而酯型儿茶素EGCG相对含量有所下降。qRT-PCR分析显示蔗糖诱导了茶树幼苗中C4H、CHS、CHI、F3H、LAR、ANR、DFR、F3’H、F3’5’H基因表达,其中变化最明显的是F3H,其次是ANR、CHS。这进一步证实了F3H、ANR为茶树儿茶素合成的关键基因。

Catechins are important secondary metabolites and functional components in tea plant [Camelliasinensis （L.） O.Kuntze] and have a broad pharmacological activities on human health. Thus, determination ofcatechins content in tea or tea products and understanding of the biosynthesis and regulation of catechins are im-portant. In this paper, the effect of sucrose on catechins biosynthesis was studies via vanillin-HC1 colorimetricanalysis and HPLC. The influence of sucrose on the expression of genes involved in catechins biosynthesis wasanalyzed using qRT-PCR. The results showed that the content and components of eatechins increased in both teacalluses and seedlings after sucrose treatment. However, a high concentration of sucrose inhibited callus growth,especially added at the early stage of callus liquid-culture. More nongalloylated catechins C and EC accumulatedin tea calluses after adding an appropriate amount of sucrose and the content ofnongalloylated catechins EGC andEC also increased in tea seedlings. However, the content of galloylated catechins EGCG declined. Sucrose in-duced the expression of C4H, CHS, CHI, F3H, LAR, ANR, DFR, F3 ＇H, F3 ＇5 ＇H in tea seedlings in which F3Hwas most significantly induced, followed by ANR and CHS, indicating that F3H and ANR might be two key genesfor catechins biosynthesis in tea.