de Freitas Pereira Maíra, Veneault-Fourrey Claire, Vion Patrice, Guinet Fréderic, Morin Emmanuelle, Barry Kerrie W, Lipzen Anna, Singan Vasanth, Pfister Stephanie, Na Hyunsoo, Kennedy Megan, Egli Simon, Grigoriev Igor, Martin Francis, Kohler Annegret, Peter Martina
Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1136 Interactions Arbres, Microorganismes, Laboratoire D'excellence Recherches Avancés sur la Biologie de l'Arbre et les Ecosystémes Forestiers, Centre Institut National de la Recherche Agronomique-Lorraine, Champenoux, France.
Swiss Federal Research Institute WSL, Forest Dynamics, Birmensdorf, Switzerland.
Front Microbiol. 2018 Feb 13;9:141. doi: 10.3389/fmicb.2018.00141. eCollection 2018.
is an ectomycorrhizal fungus with global distribution in numerous habitats and associates with a large range of host species including gymnosperm and angiosperm trees. Moreover, is the unique ectomycorrhizal species within the clade Dothideomycetes, the largest class of Ascomycetes containing predominantly saprotrophic and many devastating phytopathogenic fungi. Recent studies highlight that mycorrhizal fungi, as pathogenic ones, use effectors in form of Small Secreted Proteins (SSPs) as molecular keys to promote symbiosis. In order to better understand the biotic interaction of with its host plants, the goal of this work was to characterize mycorrhiza-induced small-secreted proteins (MiSSPs) that potentially play a role in the ectomycorrhiza formation and functioning of this ecologically very important species. We combined different approaches such as gene expression profiling, genome localization and conservation of MiSSP genes in different strains and closely related species as well as protein subcellular localization studies of potential targets of MiSSPs in interacting plants using in tobacco leaf cells. Gene expression analyses of interacting with (pine) and × (poplar) showed that similar sets of genes coding for secreted proteins were up-regulated and only few were specific to each host. Whereas pine induced more carbohydrate active enzymes (CAZymes), the interaction with poplar induced the expression of specific SSPs. We identified a set of 22 MiSSPs, which are located in both, gene-rich, repeat-poor or gene-sparse, repeat-rich regions of the genome, a genome showing a bipartite architecture as seen for some pathogens but not yet for an ectomycorrhizal fungus. Genome re-sequencing data of 15 strains and two close relatives and were used to study sequence conservation of MiSSP-encoding genes. The 22 MiSSPs showed a high presence-absence polymorphism among the studied strains suggesting an evolution through gene gain/gene loss. Finally, we showed that six CgMiSSPs target four distinct sub-cellular compartments such as endoplasmic reticulum, plasma membrane, cytosol and tonoplast. Overall, this work presents a comprehensive analysis of secreted proteins and MiSSPs in different genetic level of opening a valuable resource to future functional analysis.
是一种外生菌根真菌，在全球众多生境中均有分布，与包括裸子植物和被子植物在内的多种寄主物种共生。此外，它是座囊菌纲中唯一的外生菌根物种，座囊菌纲是子囊菌门中最大的一个纲，主要包含腐生菌和许多具有破坏性的植物病原真菌。最近的研究表明，菌根真菌与病原真菌一样，利用小分泌蛋白（SSPs）形式的效应子作为促进共生的分子钥匙。为了更好地理解其与寄主植物的生物相互作用，本研究的目的是鉴定在这种生态上非常重要的物种的外生菌根形成和功能中可能发挥作用的菌根诱导小分泌蛋白（MiSSPs）。我们结合了不同的方法，如基因表达谱分析、MiSSP基因在不同菌株和近缘物种中的基因组定位和保守性分析，以及利用烟草叶细胞对相互作用植物中MiSSPs潜在靶标的蛋白质亚细胞定位研究。与松属植物（松树）和杨属植物（杨树）相互作用的基因表达分析表明，编码分泌蛋白的相似基因集被上调，只有少数基因对每个寄主具有特异性。松树诱导更多的碳水化合物活性酶（CAZymes），而与杨树的相互作用则诱导了特定SSPs的表达。我们鉴定出一组22个MiSSPs，它们位于该基因组中富含基因、重复序列少或基因稀少、重复序列丰富的区域，该基因组呈现出一种二分结构，类似于一些病原体，但外生菌根真菌尚未有此情况。利用15个菌株以及两个近缘种和的基因组重测序数据来研究编码MiSSP基因的序列保守性。这22个MiSSPs在所研究的菌株中表现出高度的存在-缺失多态性，表明其通过基因获得/基因丢失而进化。最后，我们表明6个CgMiSSPs靶向4个不同的亚细胞区室，如内质网、质膜、细胞质和液泡膜。总体而言，这项工作对不同遗传水平下的分泌蛋白和MiSSPs进行了全面分析，为未来的功能分析提供了宝贵的资源。
