基于分泌蛋白质组学的香蕉枯萎病菌致病分子机理解析

Banana Fusarium wilt, caused by Fusarium oxysporum f.sp. cubense (Foc), is one of the most important diseases that causes the greatest reductions in banana yield worldwide. Despite the global importance, little is known about the mechanisms of Foc pathogenesis. Secreted proteins can act as pathogenicity factors and play important roles in the Foc-banana interactions. With the completion of Foc genome sequences and continued refining of the gene annotation, secretome is becoming an increasingly powerful tool for the investigation of complex pathogenesis in this important fungal pathogen. In order to access the secretome of Foc, race 1 and race 4 of Foc (Foc1 and Foc4) were grown in liquid culture with banana plant extracts as the sole nutrient source to mimic the host-pathogen interaction. A gel-free proteomics approach was employed to identify the proteins secreted into the culture medium by using isobaric tags for relative and absolute quantitation (iTRAQ)-based comparative secretomic approaches. The prediction of the protein function and the analysis of their biological function will also be conducted by bioinformatics analysis, gene knockout and functional complementation. The better understanding of the changes of secreted proteins in Foc1 and Foc4 under different conditions may provide new insights into the pathogenesis mechanisms of Foc. To our best knowledge, it is the first attempt to analyze Foc secretome on proteome-wide scale in the current proposal, which will help to understand the mechanism of the Foc-banana interactions.

尖孢镰刀菌古巴专化型（Fusarium oxysporum f. sp. cubense，Foc）引起的枯萎病是香蕉的毁灭性病害，目前对于其致病机理尚不清楚。分泌蛋白作为一类重要的致病因子，已被证实在Foc与香蕉的相互作用中起着重要作用，但目前还没有关于Foc分泌蛋白整体上的研究报道。Foc基因组测序及注释的完成，为Foc分泌蛋白质组研究提供了便利。本项目以危害我国植蕉区的2个重要Foc小种（Foc1和Foc4）为对象，通过分泌蛋白的诱导和提取，采用基于iTRAQ的蛋白质组学技术，比较分析不同诱导条件下Foc分泌蛋白的表达差异；通过生物信息学技术对Foc分泌蛋白进行功能预测和致病相关因子的筛选，并应用基因敲除与功能互补等技术对重要Foc分泌蛋白进行生物学功能分析。本项目对于更全面了解Foc的致病分子机理及不同生理小种间的致病性差异具有重要意义，也有利于更好地了解Foc与香蕉的早期互作机理。

尖孢镰刀菌古巴专化型引起的枯萎病是香蕉的毁灭性病害，目前对于其致病机理尚不清楚。分泌蛋白作为一类重要的致病因子，已被证实在Foc与香蕉的相互作用中起着重要作用，但目前还没有关于Foc分泌蛋白整体上的研究报道。本项目以危害我国植蕉区的2个重要Foc小种（Foc1和Foc4）为对象，通过分泌蛋白的诱导和提取，采用基于质谱的定量蛋白质组学技术，比较分析了不同诱导条件下Foc分泌蛋白的表达差异。在香蕉根组织诱导条件下，获得Foc4差异表达的分泌蛋白质210个，Foc1差异表达分泌蛋白质154个；通过生物信息学分析，这些差异表达分泌蛋白主要参与了代谢过程、程序性细胞死亡、生物过程调控和应激反应等重要生物学过程，其中次生代谢产物合成和酪氨酸代谢途径等与致病性相关的通路受显著影响。应用基因敲除与功能互补等技术对其中4个Foc4差异分泌蛋白进行生物学功能分析，发现敲除突变体∆Focwm和∆Fopdcd5对巴西蕉的致病力显著降低，FoCWM和FoPDCD5分泌蛋白可能为香蕉枯萎病菌的致病因子。本项目对于更全面了解Foc的致病分子机理及不同生理小种间的致病性差异具有重要意义，也有利于更好地了解Foc与香蕉的早期互作机理。