PDF(Pubmed)
Abstract：
Filamentous plant pathogens deliver effector proteins into host cells to suppress host defence responses and manipulate metabolic processes to support colonization. Understanding the evolution and molecular function of these effectors provides knowledge about pathogenesis and can suggest novel strategies to reduce damage caused by pathogens. However, effector proteins are highly variable, share weak sequence similarity and, although they can be grouped according to their structure, only a few structurally conserved effector families have been functionally characterized to date. Here, we demonstrate that Zinc-finger fold (ZiF) secreted proteins form a functionally diverse effector family in the blast fungus Magnaporthe oryzae. This family relies on the Zinc-finger motif for protein stability and is ubiquitously present in blast fungus lineages infecting 13 different host species, forming different effector tribes. Homologs of the canonical ZiF effector, AVR-Pii, from rice infecting isolates are present in multiple M. oryzae lineages. Wheat infecting strains of the fungus also possess an AVR-Pii like allele that binds host Exo70 proteins and activates the immune receptor Pii. Furthermore, ZiF tribes may vary in the proteins they bind to, indicating functional diversification and an intricate effector/host interactome. Altogether, we uncovered a new effector family with a common protein fold that has functionally diversified in lineages of M. oryzae. This work expands our understanding of the diversity of M. oryzae effectors, the molecular basis of plant pathogenesis and may ultimately facilitate the development of new sources for pathogen resistance.
摘要：
丝状植物病原体将效应蛋白递送到宿主细胞中以抑制宿主防御反应并操纵代谢过程以支持定植。了解这些效应物的进化和分子功能提供了有关发病机理的知识，并可以提出减少病原体造成的损害的新策略。然而,效应蛋白是高度可变的，共享弱序列相似性，尽管它们可以根据它们的结构进行分组，迄今为止,只有少数结构保守的效应子家族在功能上得到了表征.这里,我们证明，锌指折叠（ZiF）分泌的蛋白质在稻瘟病菌中形成了功能多样的效应子家族。该家族依赖于锌指基序的蛋白质稳定性，并且普遍存在于感染13种不同宿主物种的稻瘟病菌谱系中，形成不同的效应器部落。经典ZiF效应器的同系物，AVR-Pii,来自水稻的感染分离株存在于多个米曲霉谱系中。真菌的小麦感染菌株还具有AVR-Pii样等位基因,其结合宿主Exo70蛋白并激活免疫受体Pii。此外，ZiF部落的蛋白质可能会有所不同，表明功能多样化和复杂的效应子/宿主相互作用组。总之,我们发现了一个具有共同蛋白质折叠的新效应子家族，该家族在米曲霉谱系中具有功能多样性。这项工作扩大了我们对米曲霉效应子多样性的理解，植物致病的分子基础，并可能最终促进开发新的病原体抗性来源。
