Effect of low-intensity white light mediated de-etiolation on the biosynthesis of polyphenols in tea seedlings
Effect of low-intensity white light mediated de-etiolation on the biosynthesis of polyphenols in tea seedlings
复制标题
低强度白光介导的去黄化对茶苗多酚生物合成的影响
DOI：
10.1016/j.plaphy.2014.04.016
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发表时间：
2014-07-01
影响因子：
6.5
通讯作者：
Xia, Tao
中科院分区：
文献类型：
--
作者：
Lu, Zhongwei;Liu, Yajun;Xia, Tao
光是植物体内多种次生代谢产物合成和积累的重要能量来源和环境信号。茶多酚是茶叶中主要的次生代谢产物，具有潜在的抗氧化活性。为探讨光信号对茶树幼苗多酚生物合成和积累的调控作用，采用低强度白色光，研究了茶树幼苗多酚含量变化趋势、基因表达模式及相应酶活性的变化。LC-TOF/MS分析表明，光信号促进了羟基肉桂酸衍生物和非没食子酰化儿茶素（EGC）的积累，而抑制了β-glucogallin和没食子酰化儿茶素的积累。定量RT-PCR分析表明，非别酰化儿茶素的光形态建成和生物合成途径中的调控基因和结构基因的表达水平均上调。与此相反，DHD/SDH和UGT基因的表达，可能参与β G的生物合成途径，下调。相应的体外酶测定显示，在去黄化过程中，ECGT（没食子酰化非没食子酰化儿茶素）的活性降低，GCH（水解没食子酰化儿茶素）的活性增加。本研究得到了不一致的积累模式的酚酸，黄烷-3-醇，黄酮醇在茶树幼苗去黄化过程中。此外，茶多酚的生物合成、水解、糖基化和没食子酸化可能共同影响儿茶素的积累。(C)2014年Elsevier Masson SAS。All rights reserved.
Light is an important source of energy as well as environmental signal for the regulation of biosynthesis and accumulation of multiple secondary metabolites in plants. Polyphenols are the major class of secondary metabolites in tea, which possess potential antioxidant properties. In order to investigate the effect of light signal on the regulation of biosynthesis and accumulation of polyphenols in tea seedlings, a low-intensity white light was used and the change in trends of polyphenol contents, patterns of gene expression, and corresponding enzymatic activities were studied. LC-TOF/MS analysis revealed that light signal promoted the accumulation of hydroxycinnamic acid derivatives and nongalloylated catechin (EGC), while it restrained the accumulation of beta-glucogallin and galloylated catechins. The quantitative reverse transcription-PCR analysis showed that the expression levels of the regulator genes and some structural genes involved in photomorphogenesis and biosynthetic pathway of nongalloylated catechins, respectively, were up-regulated. In contrast, the expression of DHD/SDH and UGT genes, which may be involved in biosynthetic pathway of beta G, was down-regulated. The corresponding in vitro enzyme assays revealed decrease in the activity of ECGT (galloylates nongalloylated catechins) and an increase in activity of GCH (hydrolyzes galloylated catechins) during de-etiolation. The present study yielded inconsistent accumulation patterns of phenolic acids, flavan-3-ols, and flavonols in tea seedlings during de-etiolation. In addition, the accumulation of catechins was possibly jointly influenced by the biosynthesis, hydrolysis, glycosylation, and galloylation of polyphenols in tea plants. (C) 2014 Elsevier Masson SAS. All rights reserved.