Understanding the Phylogeny, Evolution and Host Specificity of the Exobasidiales (Ustilaginomycotina)

了解外担子目（Ustilaginomycotina）的系统发育、进化和宿主特异性

• 批准号: 431609249
• 负责人: Professor Dr. Dominik Begerow
• 金额: --
• 依托单位: National Natural Science Foundation of China
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/431609249?language=en
• 关键词: Understanding; Phylogeny; Evolution; Host; Specificity

Plant parasites constitute one of the largest ecological groups of fungi. The two major lineages that radiated once land plants were covering the planet, harbour several groups, which are exclusively plant parasitic. Although the Ascomycota and Basidiomycota evolved in direct interaction with their hosts, present data suggest, that the plant parasitic life-style has emerged several times. This is especially true, if we consider host-specific parasites like powdery mildews, rust or smut fungi. These host specific plant parasites are not only relevant as important drivers of evolution, but they represent also the largest threat to our major crop plants. E.g. all cereals are threatened by these three host specific fungal lineages and these fungi are responsible for a large economic loss each year.Major contributions have been made to the general understanding of virulence factors of Ustilaginomycotina. Ustilago maydis was the first fungal parasite, of which the genome has been fully sequenced. And in contrast to many other fungal plant parasites it can be easily grown in axenic conditions and is available for many genetic tools. The Ustilaginomycotina in total comprise more than 1700 species, most of which are highly host specific and in the meanwhile a few species have been studied in more detail. Comparative genomics and revers genetics have revealed, that so-called core effectors are important virulence factors being essential for the infection of the plant. However, the analyses of more distantly related species failed to identify factors relevant for host specificity. Therefore, we propose to use the order of Exobasidiales (Ustilaginomycotina) as a study case to identify and study factors relevant for host specificity. In contrast to the relatives of Ustilago maydis, the species of Exobasidium are very common and easy to find and isolated. A complementary sampling in China and Europe would allow to compare two lineages of closely related species. Thus, comparative genomics will go beyond the identification of core effectors, as more detailed analyses like studies of synteny, selection analyses or even transcriptomics will allow much more informative approaches. Therefore, based on 40-50 additional genomes, we will provide a phylogeny of the Exobasidiales to analyse trait evolution among and within the respective lineages. We would pay special attention to the analysis of the secretome, but we will include all informative aspects of the genomes. Additionally, we plan to use electron microscopy to study the ultrastructure of the interaction apparatus, as this might be an additional trait for host specificity. By applying these various approaches we want to analyse 1) the nutrition mode of various lineages, 2) the evolution of the sex-loci and potential sex chromosomes, 3) the evolution of effector pools of respective lineages and species, 4) morphological traits to integrate these data in the genome evolution in Ustilaginomycotina.

植物寄生虫是真菌最大的生态类群之一。曾经覆盖着地球的陆地植物曾经辐射的两个主要谱系，藏匿着几个专门寄生植物的群体。尽管子囊菌门和担子菌门是在与寄主的直接相互作用中进化的，但目前的数据表明，这种植物的寄生生活方式已经出现了几次。如果我们考虑白粉病、锈菌或黑粉菌等寄主特有的寄生虫，情况尤其如此。这些寄主特有的植物寄生虫不仅是进化的重要驱动力，而且也是对我们主要农作物的最大威胁。例如，所有的谷物都受到这三种寄主特有的真菌谱系的威胁，这些真菌每年都造成巨大的经济损失。这对全面了解黑粉菌的毒力因素做出了重大贡献。玉米黑粉菌是第一种已完成基因组测序的真菌寄生虫。与许多其他真菌植物寄生虫不同，它可以很容易地在无菌条件下生长，并可用于许多遗传工具。黑粉菌共有1700多种，其中大部分是高度寄主专化性的，同时也有少数种类得到了较详细的研究。比较基因组学和反向遗传学揭示，所谓的核心效应因子是重要的毒力因子，对植物的侵染是必不可少的。然而，对更远缘物种的分析未能确定与寄主专一性相关的因素。因此，我们建议使用外轮虫目(Ustilaginmycotina)作为研究案例，以识别和研究与寄主专一性相关的因素。与玉米黑粉菌的近缘种相比，粉锈菌的种类非常常见，很容易被发现和隔离。在中国和欧洲进行互补采样，可以比较两个近缘物种的谱系。因此，比较基因组学将超越核心效应的识别，因为更详细的分析，如共性研究，选择分析，甚至转录组分析，将允许更多的信息方法。因此，基于40-50个额外的基因组，我们将提供外胆囊虫的系统发育图，以分析各自谱系之间和内部的特征进化。我们将特别注意对分泌组的分析，但我们将包括基因组的所有信息方面。此外，我们计划使用电子显微镜来研究相互作用装置的超微结构，因为这可能是宿主特异性的另一个特征。通过应用这些不同的方法，我们想要分析1)不同谱系的营养模式，2)性基因座和潜在的性染色体的进化，3)各个谱系和物种的效应池的进化，4)形态特征，以将这些数据整合到菌丝菌的基因组进化中。