新型抑菌活性物质DMTS作用于胶孢炭疽菌麦角固醇生物合成的机制

Mango (Mangifera indica L.), one of the most important tropical fruit in China, are driving Chinese farmers out of poverty. The mango anthracnose caused by Colletotrichum gloeosporioides is seriously affecting mango yields and qualities. In previous works, our research group have found that a novel antifungal activity DMTS displayed strong inhibitory effects on C. gloeosporioides from mango and could cause serious damage to integrity of cell membranes. As well, DMTS significantly suppressed the expression of the genes on ergosterol biosynthesis pathway by analyzing gene expression profiles. However, its mechanisms of action on ergosterol biosynthesis of C. gloeosporioides have not been well characterized to date. This project plans are as follows. (1) Getting the key gene (target gene) that works with DMTS by detecting the expression of all genes on ergosterol biosynthesis pathway. (2) Confirming the target gene function by protein location, gene overexpression, knockout and complementation assays. (3) Analyzing the correlation between target gene and antifungal activity of DMTS by the phenotypes of gene silence transformants and the sensitivity of transformants to DMTS. (4) Screening the proteins that interact with DMTS and analyzing the relationship between proteins and expression of target gene. The results in this study will help us understand the molecular mechanisms of antifungal action of DMTS, and provide basis for improving the application of DMTS.

芒果是我国重要的热带水果，推动着产区农民脱贫致富，由胶孢炭疽菌引起的炭疽病严重影响着芒果的产量和品质。课题组前期发现一种新型抑菌活性物质二甲基三硫醚（DMTS）对芒果胶孢炭疽菌具有良好的抑制作用和防病效果，可破坏其细胞膜的完整性，比较分析其基因表达谱，发现麦角固醇生物合成途径的基因被显著抑制表达，但DMTS作用于胶孢炭疽菌麦角固醇生物合成的机制尚不清楚。本项目拟：（1）通过检测整个麦角固醇合成途径基因表达情况，找到与DMTS作用的关键基因（目标基因）；（2）通过蛋白亚细胞定位、基因超量表达和敲除互补策略确定目标基因的功能；（3）结合基因沉默转化子表型及基因沉默转化子对DMTS的敏感性，解析目标基因与DMTS抑菌活性的相关性；（4）筛选与DMTS互作的蛋白，分析蛋白与目标基因表达的关系。研究结果将有助于理解DMTS抑菌作用分子机理，为今后提高DMTS应用效果奠定基础。

由胶孢炭疽菌引起的芒果炭疽病严重影响芒果的产量和品质。课题组在球孢链霉菌中发现一种新型抑菌活性物质二甲基三硫醚（DMTS）对芒果胶孢炭疽菌具有良好的抑制作用，可破坏其细胞膜的完整性，抑制麦角固醇生物合成途径基因的表达。在该项目的资助下：（1）完善了DMTS对胶胞炭疽菌表观抑制作用机理的研究；（2）明确了DMTS可抑制胶胞炭疽菌中麦角固醇的合成；（3）找到了麦角固醇生物合成途径与DMTS作用的4个关键基因，分别为Cgerg1、Cgerg4、Cgerg6、Cgerg11；（4）通过基因敲除互补策略获得了4个关键基因的敲除互补转化子，研究了敲除互补转化子生物学特性、DMTS作用下麦角固醇含量以及对DMTS的敏感性，以此明确了DMTS与Cgerg6、Cgerg11存在更为紧密的互作关系；（5）明确了DMTS对不同寄主病原菌及全国芒果胶孢炭疽菌的抑制效果及对芒果采后炭疽病最佳处理时长及处理浓度；（6）获得了抗DMTS的炭疽菌菌株，从转录组水平筛选到了显著差异表达基因，为下一步更为精准地研究DMTS抑菌作用机制奠定了基础；（7）发表SCI论文3篇，其中1篇为封面论文，申请发明专利3个，其中获授权1个。研究结果将有助于理解DMTS抑菌作用机理，为后续深入研究DMTS抑菌作用机制和提高DMTS效用奠定基础。