木霉Harzianolide的合成途径和生物学功能研究

Harzianolide是多株生防哈茨木霉聚酮类次级代谢产物中，具有拮抗病原真菌，有效促进植物根系生长，诱导植物抗性，显著降低发病率。但Harzianolide合成基因簇、合成途径及其在木霉菌中的生物学功能未有深入研究。哈茨木霉NJAU 4742具有高效拮抗和促生能力，已将其研制成生物有机肥并产业化推广。从NJAU 4742发酵液中分离和鉴定聚酮Harzianolide，转录组分析NJAU 4742合成聚酮合酶（PKS）基因的转录水平分析与Harzianolide合成关联的PKS；结合基因敲除鉴定参与合成Harzianolide的PKS9。本项目将解析Harzianolide合成基因簇，研究核心蛋白PKS9的功能，推导其合成途径，为提高工程菌株合成Harzianolide水平奠定基础；通过突变子菌落表型特征阐述木霉中Harzianolide的生物学功能。

Harzianolide, an antifungal metabolite of the several biological control agent Trichoderma harzianum, has the function of antagonism to phytopathogenic fungi and increasing of plants roots, inducing systemic resistance and reducing the disease incidence. The genes cluster and synthetic pathway of Harzianolide were not reported in past research. The microbiological function of Harzianolide in Trichoderma spp. wasn’t clear. Trichoderma harzianum NJAU 4742(NJAU 4742), has prominent antagonism to pathogen fungi and improves plants growth. NJAU 4742-based organic fertilizers were developed and applied widely. Harzianolide was isolated and characterized in the fermentation broth of NJAU 4742, in the fundamental experiment. The genes related to plant resistance were up-regulated notably. The PKS9 involved in synthetized Harzianolide were fixed, combining transcriptomic analysis of PKS genes and genes deleting. This project will completely confirm the genes cluster for synthetizing Harzianolide. With the function research of the core gene PKS9, the synthetic pathway will be deduced, contributing to raise the ability to synthetize Harzianolide in the engineering strain. Exploring phenotype and metabolites of mutants will help to understand the biological function of Harzianolide in Trichoderma spp..