Global analysis of host targets of pathogen effector using yeast genetic array system

许多植物和动物的细菌病原体利用特殊的分泌装置，如III型分泌系统，将效应蛋白直接注入宿主细胞细胞质。因此，易位的效应蛋白操纵宿主细胞过程，促进感染并最终导致疾病。本研究旨在利用酵母表达系统分析植物病原菌青枯雷尔氏菌的致病因子，揭示青枯雷尔氏菌侵染的分子机制。通过对青枯菌GMI1000菌株38个效应物的筛选，我们鉴定出5个对酵母细胞有严重生长抑制作用的效应物。其中一个效应物，REY4蛋白，它有一个跨门保守的结构域，被酵母基因阵列系统分析以确定酵母中的细胞靶标(S)。这一筛选证明，与野生型细胞相比，具有细胞壁完整性MAPK级联缺陷的突变体对REY4的表达高度敏感。这一结果表明，REY4抑制了S途径，该途径在遗传上与细胞壁完整性图激酶级联相互作用。

Numerous bacterial pathogens of plants and animals utilize specialized secretion apparatus such as the type III secretion system to inject effector proteins directly into the host cell cytoplasm. Consequently, translocated effector proteins manipulate host cellular processes to promote infection and ultimately cause disease. In this study, we aimed to analyze the pathogen effectors from the plant pathogenic bacteria, Ralstonia solanacearum using yeast expression system and reveal the molecular mechanism of the strategy for R. solanacearum infection. Through the screening of 38 effectors from R. solanacearum GMI1000, we identified 5 effectors that caused sever growth inhibition to yeast cells. One of these effectors, REY4 protein, which has a domain conserved across phyla, was analyzed by the yeast genetic array system to identify the cellular target(s)in yeast. This screening identified that mutants having defect in the cell wall integrity MAP kinase cascade are hyper-sensitive to REY4-expression compared to wild-type cells. This result suggests that REY4 inhibits the pathway(s), which genetically interacts with the cell wall integrity MAP kinase cascade.