Franceschetti Marina, Maqbool Abbas, Jiménez-Dalmaroni Maximiliano J, Pennington Helen G, Kamoun Sophien, Banfield Mark J
Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich, United Kingdom.
The Sainsbury Laboratory, Norwich Research Park, Norwich, United Kingdom.
Microbiol Mol Biol Rev. 2017 Mar 29;81(2). doi: 10.1128/MMBR.00066-16. Print 2017 Jun.
Fungi and oomycetes are filamentous microorganisms that include a diversity of highly developed pathogens of plants. These are sophisticated modulators of plant processes that secrete an arsenal of effector proteins to target multiple host cell compartments and enable parasitic infection. Genome sequencing revealed complex catalogues of effectors of filamentous pathogens, with some species harboring hundreds of effector genes. Although a large fraction of these effector genes encode secreted proteins with weak or no sequence similarity to known proteins, structural studies have revealed unexpected similarities amid the diversity. This article reviews progress in our understanding of effector structure and function in light of these new insights. We conclude that there is emerging evidence for multiple pathways of evolution of effectors of filamentous plant pathogens but that some families have probably expanded from a common ancestor by duplication and diversification. Conserved folds, such as the oomycete WY and the fungal MAX domains, are not predictive of the precise function of the effectors but serve as a chassis to support protein structural integrity while providing enough plasticity for the effectors to bind different host proteins and evolve unrelated activities inside host cells. Further effector evolution and diversification arise via short linear motifs, domain integration and duplications, and oligomerization.
真菌和卵菌是丝状微生物，其中包括多种高度进化的植物病原体。它们是植物生理过程的复杂调节因子，能分泌一系列效应蛋白，作用于多个宿主细胞区室，从而引发寄生性感染。基因组测序揭示了丝状病原体效应蛋白的复杂目录，有些物种含有数百个效应基因。尽管这些效应基因中的很大一部分编码的分泌蛋白与已知蛋白的序列相似性很低或没有相似性，但结构研究揭示了多样性之中意想不到的相似性。本文根据这些新见解，综述了我们对效应蛋白结构和功能的理解进展。我们得出结论，有新证据表明丝状植物病原体效应蛋白存在多种进化途径，但有些家族可能是通过复制和多样化从共同祖先扩展而来。保守的折叠结构，如卵菌的WY结构域和真菌的MAX结构域，虽然不能预测效应蛋白的确切功能，但可作为一个框架，支持蛋白质的结构完整性，同时为效应蛋白提供足够的可塑性，使其能够结合不同的宿主蛋白，并在宿主细胞内进化出不相关的活性。效应蛋白的进一步进化和多样化是通过短线性基序、结构域整合与复制以及寡聚化实现的。
