A tyrosine decarboxylase catalyzes the initial reaction of the salidroside biosynthesis pathway in Rhodiola sachalinensis
A tyrosine decarboxylase catalyzes the initial reaction of the salidroside biosynthesis pathway in Rhodiola sachalinensis
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DOI：
10.1007/s00299-011-1053-7
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发表时间：
2011-08-01
影响因子：
6.2
通讯作者：
Wang, You-Nian
中科院分区：
文献类型：
--
作者：
Zhang, Ji-Xing;Ma, Lan-Qing;Wang, You-Nian
红景天苷是酪醇的8-O-β-D-葡萄糖苷，是红景天属植物的主要生物活性成分，主要存在于植物根部。众所周知，酪醇的葡糖基化是红景天苷生物合成的最后一步;然而，酪醇的生物合成途径及其调控还不太清楚。综合相关研究结果表明，酪醇的前体可能是由酪氨酸合成的酪胺。本研究从高山红景天（Rhodiola sachalinensis A.）Bor使用cDNA末端的快速扩增。将所得cDNA命名为RsTyrDC。RNA凝胶印迹分析显示，在植物中的主要表达位点是根，并且在愈伤组织培养物中也发现了高水平的转录物。功能分析表明酪氨酸是重组RsTyrDC的最佳底物。正义RsTyrDC的过表达导致酪醇和红景天苷含量的显著增加，但在反义RsTyrDC转化系中酪醇和红景天苷的水平分别比对照低274%和412%。本研究结果为RsTyrDC调控酪醇和红景天苷的生物合成提供了体内外证据，并且RsTyrDC很可能在红景天苷生物合成途径的起始反应中起重要作用。萨氏藻
Salidroside, the 8-O-beta-D-glucoside of tyrosol, is the main bioactive component of Rhodiola species and is found mainly in the plant roots. It is well known that glucosylation of tyrosol is the final step in the biosynthesis of salidroside; however, the biosynthetic pathway of tyrosol and its regulation are less well understood. A summary of the results of related studies revealed that the precursor of tyrosol might be tyramine, which is synthesized from tyrosine. In this study, a cDNA clone encoding tyrosine decarboxylase (TyrDC) was isolated from Rhodiola sachalinensis A. Bor using rapid amplification of cDNA ends. The resulting cDNA was designated RsTyrDC. RNA gelblot analysis revealed that the predominant sites of expression in plants are the roots and high levels of transcripts are also found in callus tissue culture. Functional analysis revealed that tyrosine was best substrate of recombinant RsTyrDC. The over-expression of the sense-RsTyrDC resulted in a marked increase of tyrosol and salidroside content, but the levels of tyrosol and salidroside were 274 and 412%, respectively, lower in the antisense-RsTyrDC transformed lines than those in the controls. The data presented here provide in vitro and in vivo evidence that the RsTyrDC can regulate the tyrosol and salidroside biosynthesis, and the RsTyrDC is most likely to have an important function in the initial reaction of the salidroside biosynthesis pathway in R. sachalinensis.