内生真菌Lasiodiplodia pseudotheobromae (LPS-1) 抗菌活性物质的鉴定及其抑制小麦白粉菌机理的研究

Endophytic fungi were important source of bioactive natural products, discoveries of new bio-control resources and lead compounds are becoming an important prerequisite and foundation for development of bio-pesticides.Early work of screening medicinal plant endophytic fungi lead to finding of Lasiodiplodia pseudotheobromae (LPS-1). LPS-1 fermentation broth showed more than 80% efficacy to Blumeria graminis f.sp. tritici (BGT) on wheat leaves in vitro, active components A11(100μg/mL ) showed 18.7% and 86.9% inhibition to conidia germination and haustorium formation respectively, implying its bioactivity is mainly on haustorium formation stage.But the active substances of LPS-1 and the mechanism for its effects on haustorium formation remain unclear.In this study, we are planning to utilize various spectroscopic techniques to identify the structure of active substances; observe the impact of active compounds to BGT morphology and sub-cellular structure with electron microscope; analyze critical genes and metabolic pathway regulated by active compounds with RNA-seq technology.This work intends to identify 1-2 active compounds for development and utilization of antifungal biochemical, as well as building theoretical basis for applying the fungi as pesticide to control wheat powdery mildew.

内生真菌是天然活性物质的重要来源，发现新的生防资源和先导化合物是开发生物农药的重要前提和基础。申请者筛选到药用植物内生真菌类柯柯豆毛色二孢Lasiodiplodia pseudotheobromae (LPS-1)，LPS-1发酵液对小麦白粉菌离体叶段防效在80%以上，活性组分A11(100μg/mL)对孢子萌发和吸器形成抑制率分别为18.7%和86.9%，表明A11主要作用在吸器形成阶段。但LPS-1的活性物质及其影响吸器形成的机理并不清楚。本研究运用各种波谱技术进行活性物质结构鉴定；采用电镜观察活性化合物对白粉菌亚细胞结构的影响；并运用RNA-seq技术分析活性化合物影响吸器形成的关键基因和代谢途径。项目拟鉴定1-2个活性化合物，为抗菌化合物的开发与利用，以及该菌作为生物农药防治小麦白粉病提供理论基础。

内生真菌是天然活性物质的重要来源，发现新的生防资源和先导化合物是开发生物农药的重要前提和基础。本研究采用Sephadex LH-20凝胶柱层析、制备型高效液相色谱等分离手段进行LPS拮抗小麦白粉病菌活性物质的分离纯化，运用各种波谱技术鉴定出3-吲哚甲醛、3-吲哚甲酸、茉莉酸和芥酸酰胺四个单体化合物；通过复配筛选出增效显著的杀菌组合物3-吲哚甲酸和茉莉酸，最佳增效配比为2:8；采用光学显微镜及电镜观察，明确杀菌组合物主要作用为抑制小麦白粉菌附着孢、吸器的形成；并运用RNA-seq技术分析组合物处理前后差异表达基因和影响吸器形成关键基因。本研究为抗菌化合物的开发与利用，以及LPS作为生物农药防治小麦白粉病提供理论基础。