产酶溶杆菌OH11中钙结合蛋白LcbP调控抗真菌活性物质HSAF生物合成的机制研究

热稳定抗真菌因子（HSAF）是产酶溶杆菌OH11产生的一种化学结构、作用方式及合成机制全新的抗真菌活性物质，可开发成环境友好型生物杀菌剂，但在野生型菌株中产量极低，限制了其进一步产业化开发。在前期研究中，申请者发现添加Ca2+对HSAF产量具有极大的促进作用，明确了钙信号途径参与此调控过程，并鉴定了钙结合蛋白LcbP。Ca2+是生物体内普遍存在的第二信使，广泛参与多种细胞代谢过程。但以前对钙信号的研究多集中于植物和真菌中，在细菌中较少，特别是对次生代谢产物生物合成的调控更是未见报道。为阐明上述机制，本项目拟将综合运用生物信息学、遗传学和分子生物学等手段，深度解析LcbP在调控HSAF合成中的功能，鉴定位于LcbP下游并参与调控HSAF合成的转录因子，并阐明转录因子对HSAF合成的调控机制。该研究成果不仅能够丰富细菌中钙信号调控机制，也可为HSAF高产工程菌株的构建提供新的靶标基因。

Heat Stable Antifungal Factor (HSAF) is an antifungal active substance produced by Lysobacter enzymogenes OH11 with a new structure, mode of action and biosynthesis mechanism. Thus, it can be developed into an environment-friendly biocide. However, the yield of HSAF is very low in the wild-type strain, which limits its further industrialization development. In early studies, we found that calcium ion had a surprisingly positive role on the HSAF production, confirmed the calcium signaling pathway involved in this regulation process, and identified an importance calcium binding proteins LcbP. Calcium signaling is a ubiquitous second messenger in organisms and widely participates in various cellular metabolic processes. Previous studies on calcium signaling mainly focused on plants and fungi, but less on bacteria, especially on the regulation of secondary metabolite biosynthesis. To further elaborate on the above mechanism, we aim to explore the physiological function of LcbP in regulating HSAF biosynthesis, identify the transcription factors for modulating HSAF biosynthesis in the downstream of LcbP, and elucidate the mechanism of the transcription factors in the regulation of HSAF by using bioinformatics, genetics and molecular biology. The results not only can supplement the mechanism of calcium signal regulation in bacteria, but also provide new key target genes for the construction of high-yield engineering strains of HSAF.