AaMYB2介导光信号和茉莉酸信号互作调控青蒿素合成的分子机理研究

Artemisinin is the first choice for the clinical treatment of Malaria, and there is huge demand of production. However, the artemisinin content in Artemisia annua is relatively low. So the intensive study on the molecular regulation of the bio-synthesis of artemisinin is very positive for genetic improvement of A. annua. It is revealed that light and JAs could both improve the production of artemisinin obviously, however, the interaction of these two factors and the underlying mechanism is still unresolved. Previously, we found that the promotion of JAs on artemisinin biosythetic genes is tightly depended on light, and we further isolated the glandular trichome specific positive regulator AaMYB2, which showed protein-protein interactin with the negative regulator of the light signaling and the JAs signaling respectively. This indicated that light and JAs could regulate AaMYB2 at different level, and so that modulate the synthesis of artemisinin. Based on these preliminary studies, we intended to further verify the regulation of AaMYB2 on the promoters of the synthetic genes of artemisinin and reveal the underlying mechanism; study the regulation of light signal and JAs on the AaMYB2 gene, either at gene expression level or protein level, and reveal the interaction of this two signals and their regulation of artemisinin biosynthesis, so that provide solid scientific foundation for cultivation of A. annua with high artemisinin content.

青蒿素是临床治疗疟疾的首选药物，需求巨大，但青蒿中含量低，因此深入研究青蒿素生物合成的分子调控机理对于遗传改良青蒿具有积极意义。研究发现茉莉酸和光都能显著提高青蒿素含量，然而，二者在调控青蒿素合成上的相互作用及其分子机制尚未研究。申请人前期研究结果显示，茉莉酸促进青蒿素合成功能基因的表达严格依赖于光，并进一步筛选到分泌性腺毛特异的青蒿素合成正调控因子AaMYB2，它能够与光信号及茉莉酸信号途径的负调控因子发生蛋白相互作用。这暗示茉莉酸和光信号通过在不同水平上调控同一个转录因子AaMYB2，从而协同调控青蒿素的合成。本项目拟在前期工作基础上，进一步明确AaMYB2对青蒿素合成功能基因启动子的调控，揭示其调控青蒿素合成的分子机理；通过研究光信号和茉莉酸信号在基因表达水平和蛋白水平对该基因的调控，初步揭示这两个信号的互作对青蒿素合成的调控机理，从而为培育高含量青蒿素的青蒿提供扎实的科学依据。

青蒿素是临床治疗疟疾的首选药物，需求巨大，但青蒿中含量低，因此深入研究青蒿素生物合成的分子调控机理对于遗传改良青蒿具有积极意义。研究发现茉莉酸和光都能显著提高青蒿素含量，然而，二者在调控青蒿素合成上的相互作用及其分子机制尚未研究。我们通过转基因手段鉴定了AaMYB2正调控青蒿素生物合成中的功能，利用分子生物学和遗传学手段发现AaMYB2通过与AaCOP1的互作介导了光信号调控青蒿素合成，AaMYB2通过与AaJAZ8的互作介导了茉莉酸信号调控青蒿素合成。从而揭示了AaMYB2介导茉莉酸和光信号互作调控青蒿素合成的分子机制。.进一步对于光信号转导途径关键因子AaHY5以及茉莉酸信号途径的关键转录因子AabHLH1的研究发现：AaHY5激活分泌型腺毛中特异表达的AaGSW1转录因子的转录从而正调控青蒿素合成，而黑暗下AaCOP1通过泛素化降解AaHY5抑制青蒿素的生物合成;而AabHLH1介导茉莉酸正调控青蒿素的方式是通过与茉莉酸信号途径的9个同源抑制因子JAZ1-9的相互作用来实现。本项目回答了“茉莉酸促进青蒿素合成为什么依赖于光”这一青蒿素代谢调控领域重要的科学问题。本研究将有助于完整解析青蒿素生物合成的调控网络，为培育高产青蒿素的青蒿品种提供理论基础。