产酶溶杆菌DSF与c-di-GMP信号途径协同调控抗菌物质HSAF生物合成的机制研究

细菌可通过复杂、交叉的信号网络感应细胞内外的环境变化调控其自身行为和生物学功能。在生防细菌中，不同信号途径协同调控抗菌次生代谢产物的研究目前还鲜有报导。HSAF是生防细菌产酶溶杆菌产生的一种次生代谢产物，前期已明确其具有广谱高效的抗真菌、卵菌活性且作用方式和生物合成机制新颖，但在野生型菌株中产量低，限制了其进一步产业化开发。近期，申请者发现DSF和c-di-GMP信号途径都能调控HSAF的生物合成，但它们间的关系及其协同调控机制未知。为此，本项目以两个途径中共有的RpfG蛋白为切入点，研究DSF与c-di-GMP信号途径对HSAF生物合成的调控作用以及RpfG蛋白的功能，鉴定以RpfG为中心的HSAF生物合成信号调控网络，阐明两个信号途径协同调控HSAF生物合成的分子机制。研究结果不仅有助于揭示细菌中不同信号途径间的协同调控机理，而且为高产菌株的构建和HSAF的产业化开发提供理论依据。

Although bacterium is unicellular organism with simple structure, it has a complex network of signaling system to sense changes inside and outside of the cells to regulate their own behavior and physiological functions. At present, in the biocontrol bacteria, there are few reports about the cross-talk by different signal pathways in regulation of the secondary antimicrobial metabolite HSAF is a kind of secondary metabolites produced by the biocontrol agent Lysobacter enzymogenes with broad-spectrum and highly effective antagonistic activity against many pathogenic fungi and oomycetes. Thus, it has the application prospect. However, the low yield of HSAF in the wild-type L. enzymogenes is the limit of its broad application. Recently, we found that RpfG located in both DSF and c-di-GMP signaling pathways and was involved in HSAF regulation, but the deeper mechanism is unknown. Therefore, we intend to elucidate the molecular mechanism of cross-talk by DSF and c-di-GMP signaling pathways in regulating HSAF biosynthesis, including the relationship between DSF signaling and the degradation of c-di-GMP by RpfG and the signaling pathway regulated by RpfG in HSAF biosynthesis. The results not only can reveal the molecular mechanism of cross-talk in regulation of the antimicrobial substances biosynthesis by different signaling pathways, but also provide a theoretical basis for obtaining high-yield strains through genetic modification.