生防因子草酸脱羧酶对木霉重寄生灰霉菌的影响机制研究

草酸是灰霉菌侵染植物的重要致病因子，木霉可利用草酸脱羧酶（OXDC）降解草酸，阻止灰霉菌侵染植物。木霉拮抗灰霉菌时，OXDC和重寄生相关的细胞壁水解酶编码基因同时上调表达。将木霉OXDC基因敲除后，突变株重寄生作用被抑制，表明木霉重寄生灰霉菌受OXDC的影响，但其机制尚未可知。为了揭示OXDC通过哪些基因和途径作用影响了重寄生，本项目以一株高效生防木霉Trichoderma afroharzianum LTR-2为研究对象，建立木霉重寄生灰霉菌分析体系，构建OXDC基因缺失和过表达突变株，利用RNA-seq分析OXDC突变株重寄生灰霉菌的转录组表达模式，获得差异表达的重寄生相关基因。进一步针对差异基因构建缺失（弱化）和过表达突变株，通过分析表型和生防特性明确差异基因功能，揭示OXDC对木霉重寄生灰霉菌的影响机制。通过本研究将获得对木霉拮抗灰霉菌机制的新认识，拓展木霉防治灰霉病的理论基础。

Oxalic acid (OA) is an important pathogenic factor of Botrytis cinerea. Trichoderma can degrade OA to prevent B. cinerea from infecting plant tissues utilizing the action of oxalate decarboxylase (OXDC). When Trichoderma antagonized B. cinerea, both OXDC and mycoparasitism-related hydrolase coding genes were up-regulated. After Trichoderma OXDC gene was knocked out, the mycoparasitism of the mutant strain was inhibited, suggesting that the mycoparasitism was affected by OXDC, but its mechanism is still unknown. In order to reveal the genes and pathways that OXDC affected in mycoparasitism, this project takes an efficient biocontrol agent, T. afroharzianum LTR-2, as the research object, and establishes an analysis system of the mycoparasitism. OXDC gene deletion and overexpression mutant strains will be constructed, and their transcriptome expression patterns during myco-parasitizing B. cinereal will be analyzed using RNA-seq. Differentially expressed genes (DEGs) related to mycoparasitism will be obtained, and the DEGs will be knocked out, knocked down, and overexpressed to identify their functions through analyzing phenotype and bio-control characteristics. Finally, the mechanism by which OXDC affects Trichoderma myco-parasitizing B. cinerea is expected. Through this study, new knowledge regarding to the mechanism of Trichoderma inhibiting B. cinerea will be acquired, and the theoretical basis of Trichoderma bio-controlling grey mould will be expanded.