SmGGPPS2对丹参酮合成的影响

香叶基香叶基焦磷酸合酶(GGPPS)是植物二萜类次生代谢物合成过程中的重要调控位点。在药用模式植物丹参(Salvia miltiorrhiza)中, GGPPS基因家族成员SmGGPPS2的生物学功能及其在丹参酮有效成分合成过程中的作用尚不明确。分别在丹参植株中过表达和RNA干涉SmGGPPS2基因, 并对转基因丹参中丹参酮含量和丹参酮合成相关基因表达量 以及转基因植物生理指标进行检测, 结果表明, 过表达SmGGPPS2株系中的丹参酮IIA和铁锈醇等脂溶性成分含量高于野生型; RNA干涉SmGGPPS2株系中的丹参酮IIA和铁锈醇等脂溶性成分含量均低于野生型。调节表达SmGGPPS2后, 丹参株系中SmHMGR1和SmCPS1等多个关键酶基因的表达都呈现明显的变化。此外, 调节表达SmGGPPS2还影响丹参植株抗性。以上结果表明, SmGGPPS2在丹参酮等萜类物质的合成中起重要的调控作用。

Effect of SmGGPPS2 Expression on Tanshinones Biosynthesis in Salvia miltiorrhiza

Geranylgerany pyrophosphate synthase (GGPPS) is an important regulator in the plant diterpenoid biosynthesis pathway. The GGPPS gene family plays a critical role in the development of the medicinal model plant Salvia miltiorrhiza. However, the biological function of SmGGPPS2, especially in the biosynthesis of tanshinone or other active ingredients, is still unclear. For functional investigation, SmGGPPS2 expression was up- or down-regulated in S. miltiorrhiza plants via overexpression or RNA interference, respectively. Then we detected the content of tanshinones, the expression of genes related to tanshinone biosynthesis, and the physiological indexes of transgenic S. miltiorrhiza plants. The content of fat-soluble components, such as tanshinone IIA and ferruginol, was increased significantly in SmGG- PPS2-overexpressed lines compared with the wild type, and the content of fat soluble-components was lower in SmGGPPS2-RNAi lines than those in the wild type lines. With the regulation of SmGGPPS2, the expression of key enzyme genes related to tanshinone biosynthesis in S. miltiorrhiza, such as SmHMGR1 and SmCPS1, was changed. In addition, the regulation of SmGGPPS2 expression also affected the resistance of S. miltiorrhiza. Our results indicate that SmGGPPS2 plays an important regulatory role in tanshinone biosynthesis.