辣椒疫霉效应子CRN173抑制生防溶杆菌中抗菌物质HSAF合成的分子机制解析

疫霉菌是一类重要的植物病原菌，基因组编码上千个效应子（效应蛋白），已知在与寄主植物互作中起到关键作用。在自然界中，微生物之间存在广泛的互作关系，包括接触依赖性生长抑制（CDI），即一种微生物会利用特定分子去抑制同生境的其它微生物。利用生防菌是病害控制的一种常用方式，我们推测疫霉菌也可能利用效应子来抵消生防菌的生防作用，因此选用了辣椒疫霉和产酶溶杆菌OH11为材料，筛选到多个效应子表现出对产酶溶杆菌不同层次的抑制作用，其中效应子CRN173能显著抑制产酶溶杆菌抗菌物质HSAF的合成，且可能是通过与HSAF合成调控的转录因子Clp互作来实现的。本项目将进一步确认CRN173抑制HSAF合成的功能，明确CRN173-Clp互作的核心结构域，着重解析效应子干扰Clp信号通路的分子机制。研究有望揭示疫霉菌效应子防御生防细菌的功能和作用机制，拓展对效应子功能的认识，为生防菌的高效使用奠定理论基础。

The genus of Phytophthora is one class of devastating plant pathogens, and it could secrete thousands of effectors. To date, only several effectors have been reported to play key roles in the interaction between pathogens and plants. In nature, there are a wide range of interactions between microorganisms, and contact-dependent growth inhibition (CDI) is a common interaction mechanism. The microorganisms use CDI system to deliver toxins into neighboring microorganisms to inhibit their growth. Using biocontrol microorganisms is a common way of disease control. We speculate that Phytophthora pathogens may also use effectors to counteract the biocontrol effect of biocontrol microorganisms. Thus, by using the interaction of P. capsici and L. enzymogenes as the working system, we screened several effectors which showed inhibition of L. enzymogenes on different levels. Among these, CRN173 could significantly inhibit the biosynthesis of HSAF, and CRN173 might interact with a transcript factor, Clp, which positively regulates the biosynthesis of HSAF. This project will further identify the core domain and key amino acids of CRN173 when it inhibits HSAF biosynthesis, and clarify the core domain for the interaction of CRN173 and Clp. We will further investigate the molecular mechanism by which CRN173 inhibits the biosynthesis of HSAF by interfering with Clp mediated signal pathways. The results are expected to reveal the molecular mechanism of effector mediated defense of Phytophthora pathogens against biocontrol bacteria, and also laid a theoretical foundation for the efficient use of biocontrol bacteria.