Department of Pharmacy, Changzheng Hospital, Second Military Medical University, Shanghai 200003, People's Republic of China.
Plant Cell Rep. 2012 Dec;31(12):2247-59. doi: 10.1007/s00299-012-1334-9. Epub 2012 Aug 29.
This study provides a desirable candidate gene resource (SmAOC) to increase the content of valuable natural products via appropriate JA pathway genetic engineering. Jasmonates (JAs) are important signal molecules in plants. They regulate transcripts of defense and secondary biosynthetic metabolite genes in response to environmental stresses. Currently, JAs are widely used as elicitors to improve the content of useful secondary metabolism in plants. Synthesis of the naturally occurring enantiomer of various jasmonates is catalyzed by allene oxide cyclase (AOC, EC 5.3.99.6). Here, we cloned and characterized the AOC gene (SmAOC) from Salvia miltiorrhiza. As expected, SmAOC expression was induced by abiotic stimuli such as methyl jasmonate (MeJA), ultraviolet radiation (UV) and low temperature (4 °C) in S. miltiorrhiza plantlets. To demonstrate whether the engineered internal JAs pool by overexpressing AOC gene could promote secondary metabolism production, the SmAOC was incorporated into S. miltiorrhiza hairy roots. The results revealed that SmAOC overexpression significant enhanced the yields of tanshinone IIA, rosmarinic acid (RA) and lithospermic acid B (LAB) in S. miltiorrhiza hairy roots. In addition, expression levels for key genes involved in the biosynthetic pathway of diterpenes and phenolic acids were also altered. These suggest that genetic manipulation of AOC would be helpful for improving the production of valuable secondary metabolites by regulating the biosynthesis of JAs.
本研究提供了一个理想的候选基因资源（SmAOC），可通过适当的 JA 途径基因工程来提高有价值天然产物的含量。茉莉酸（JAs）是植物中的重要信号分子。它们调节防御和次生生物合成代谢物基因的转录，以响应环境胁迫。目前，JAs 广泛用作诱导子，以提高植物中有用次生代谢物的含量。各种茉莉酸的天然对映异构体的合成由丙二烯氧化物环化酶（AOC，EC 5.3.99.6）催化。在这里，我们从丹参中克隆和表征了 AOC 基因（SmAOC）。正如预期的那样，SmAOC 的表达在丹参植物中受到生物胁迫刺激的诱导，如茉莉酸甲酯（MeJA）、紫外线（UV）和低温（4°C）。为了证明通过过表达 AOC 基因工程化的内部 JAs 池是否可以促进次生代谢产物的产生，将 SmAOC 整合到丹参毛状根中。结果表明，SmAOC 的过表达显著提高了丹参毛状根中丹参酮 IIA、迷迭香酸（RA）和丹参素 B（LAB）的产量。此外，还改变了二萜和酚酸生物合成途径中关键基因的表达水平。这表明 AOC 的遗传操作有助于通过调节 JAs 的生物合成来提高有价值的次生代谢产物的产量。
