禾谷镰孢菌中多拷贝基因的功能分化及其在病原菌产毒致病 过程中的作用机制研究

Gene duplication provides raw material for functional innovation, the appearance of duplicated genes and their sub-/neofunctionalization plays crucial roles in the adaption to environmental changes. We have noticed high frequency of duplicated genes in the important wheat head blight fungus Fusarium graminearum in our previous studies. Using bioinformatics prediction, we have identified 66 sets of duplicated genes (154 in total) from the genome of F. graminearum. We have constructed the deletion mutants for these duplicated genes and phenotype assays showed that most duplicated genes in F. graminearum sharing functional overlap, while some of them do have interesting functional partitioning in regulating fungal development, mycotoxin biosynthesis and pathogenesis. Based on current research, this project will further analyze the functional divergence and its molecular bases of duplicated genes in F. graminearum and elucidate evolutionary mechanism of 8 sets of duplicated genes selected from previous studies in the adaption to the environmental conditions and hosts as well as the regulating mechanisms of these duplicated genes in fungal development, DON biosynthesis and pathogenicity. Results of this project will provide molecular targets for novel fungicides development and scientific basis for strategy of controlling wheat head blight and of reducing mycotoxin contamination.

基因倍增是生物新颖性产生和维持的重要途径，多拷贝基因的出现和功能分化在生物体不断适应环境的进化过程中起关键作用，然而，多拷贝基因是如何协同分工或衍生新功能从而摒弃冗余功能的进化机制尚不清楚。麦类作物重要致病菌禾谷镰孢菌基因组中存在高频次的基因倍增现象，生物信息学比对检索到66组154个多拷贝基因，项目组前期构建了这154个基因的敲除突变体，表型测定结果显示，大多数多拷贝基因存在功能冗余现象，但也有1/5多拷贝基因在生长发育和产毒致病过程中表现功能分化。本项目将以前期筛选到的8组存在功能分化的多拷贝基因为研究对象，从转录水平、亚细胞定位和生物学表型3方面解析其在菌体生长发育和产毒致病过程中的功能分化模式，探讨病原菌借助基因倍增和多拷贝基因功能分化进行“升级装备”以提高环境和寄主适合度的进化机制，从进化的视角挖掘产毒致病新基因，为新型药剂研发提供靶标，为赤霉病防控和毒素污染治理提供理论依据。

本项目深入解析了麦类作物重要致病菌禾谷镰孢菌Fusarium graminearum基因组中多拷贝基因在菌体生长发育和产毒致病过程中的功能分化模式。通过生物信息学分析鉴定了禾谷镰孢菌中66组154个多拷贝基因，构建了上述基因的敲除突变体库，通过生物学表型测定，探讨多拷贝基因在适应环境和寄主的进化过程中功能多样性的演化机制；阐明几组多拷贝基因的功能分化模式及其在调控菌体生长发育和产毒致病过程中的作用机制，已完成项目申报书中既定的研究目标。相关研究结果为解析植物病原真菌借助基因倍增调控生长发育及产毒致病重要生理活动提供了新线索，从进化的视角挖掘产毒致病新基因，为新型药剂研发提供靶标，为赤霉病防控和毒素污染治理提供理论依据。