中药青蒿的分子生物学研究新成果
来源:《Molecular Plant》
时间：2015/10/08
第二军医大学领导的研究小组对中药青蒿（Artemisia annua）的分子生物学研究中取得突破进展，研究论文发表在9月的《Molecular Plant》杂志上。
来自第二军医大学的研究人员证实TAR1（TRICHOME AND ARTEMISININ REGULATOR 1）是青蒿中毛状体（Trichome）发育及青蒿素生物合成的必要条件。
第二军医大学药物院张磊（Lei Zhang）教授是这篇论文的通讯作者。主要从事药用植物分子生物学及次生代谢工程研究，在紫杉醇、青蒿素、莨菪碱、喜树碱、银杏黄酮/内酯、丹参和菘蓝苯丙素类成分、长春花萜类吲哚生物碱、灯盏花素等重要植物药源的生源合成和代谢调控领域开展了深入和富有原创性的研究工作。
毛状体指的是许多植物表面上的一些小突起，其能够生成和储存各种次生代谢产物。最著名及有效的疟疾药物青蒿素就是由青蒿素合成、储存及分泌。但目前对于在青蒿中调控青蒿素生物合成及毛状体发育的分子机制仍知之甚少。
在这篇文章中研究人员报告称，一种AP2转录因子——TAR1对调控青蒿中毛状体发育和青蒿素合成起重要作用。TAR1编码了一种特异定位于细胞核中的蛋白质，其主要是在嫩叶、花芽及某些毛状体中表达。在TAR1-RNAi品系中，毛状体形态和角质层蜡质组成发生改变，青蒿素含量显著减少，通过过表达TAR1则可显著提高青蒿素含量。研究人员证实当沉默或过表达TAR1时，与青蒿素生物合成相关的一些关键基因的表达水平发生了改变。通过电泳迁移率、酵母单杂交及瞬时转化β-葡糖醛酸糖苷酶检测，他们证实青蒿素生物合成信号通路中的两个重要基因ADS和CYP71AV1，有可能是TAR1的直接靶标。
这些研究结果表明了，TAR1是青蒿中毛状体发育及青蒿素生物合成调控分子网络的一个关键组件。（来源： 生物通 何嫱）
Abstract Trichomes, small protrusions on the surface of many plant species, can produce and store various secondary metabolic products. Artemisinin, the most famous and potent medicine for malaria, is synthesized, stored, and secreted by Artemisia annua trichomes. However, the molecular basis regulating the biosynthesis of artemisinin and the development of trichomes in A. annua remains poorly understood. Here, we report that an AP2 transcription factor, TRICHOME AND ARTEMISININ REGULATOR 1 (TAR1), plays crucial roles in regulating the development of trichomes and the biosynthesis of artemisinin in A. annua. TAR1, which encodes a protein specially located in the nucleus, is mainly expressed in young leaves, flower buds, and some trichomes. In TAR1-RNAi lines, the morphology of trichomes and the composition of cuticular wax were altered, and the artemisinin content was dramatically reduced, which could be significantly increased byTAR1 oeverexpression. Expression levels of several key genes that are involved in artemisinin biosynthesis were altered when TAR1 was silenced or overexpressed. By the electrophoretic mobility shift, yeast one-hybrid and transient transformation β-glucuronidase assays, we showed that ADS and CYP71AV1, two key genes in the biosynthesis pathway of artemisinin, are likely the direct targets of TAR1. Taken together, our results indicate that TAR1 is a key component of the molecular network regulating trichome development and artemisinin biosynthesis in A. annua.
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