Genomic landscape of a relict fir-associated fungus reveals rapid convergent adaptation towards endophytism
2022
Yuan, Zhilin | Wu, Qi | Xu, Liangxiong | Druzhinina, Irina | Stukenbrock, Eva | Nieuwenhuis, Bart | Zhong, Zhenhui | Liu, Zhong-Jian | Wang, Xinyu | Kubicek, Christian | Shan, Xiaoliang | Wang, Jieyu | Shi, Guohui | Peng, Long | Martin, Francis | Chinese Academy of Forestry | Chinese Academy of Sciences [Beijing] (CAS) | Huizhou University | Nanjing Agricultural University (NAU) | Vienna University of Technology (TU Wien) | Max Planck Institute for Evolutionary Biology ; Max-Planck-Gesellschaft | Ludwig-Maximilians-Universität München (LMU) | Fujian Agriculture and Forestry University (FAFU) | Interactions Arbres-Microorganismes (IAM) ; Université de Lorraine (UL)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
International audience
显示更多 [+] 显示较少 [-]英语. Comparative and pan-genomic analyses of the endophytic fungus Pezicula neosporulosa (Helotiales, Ascomycota) from needles of the relict fir, Abies beshanzuensis, showed expansions of carbohydrate metabolism and secondary metabolite biosynthetic genes characteristic for unrelated plant-beneficial helotialean, such as dark septate endophytes and ericoid mycorrhizal fungi. The current species within the relatively young Pliocene genus Pezicula are predominantly saprotrophic, while P. neosporulosa lacks such features. To understand the genomic background of this putatively convergent evolution, we performed population analyses of 77 P. neosporulosa isolates. This revealed a mosaic structure of a dozen non-recombining and highly genetically polymorphic subpopulations with a unique mating system structure. We found that one idiomorph of a probably duplicated mat1-2 gene was found in putatively heterothallic isolates, while the other co-occurred with mat1-1 locus suggesting homothallic reproduction for these strains. Moreover, 24 and 81 genes implicated in plant cell-wall degradation and secondary metabolite biosynthesis, respectively, showed signatures of the balancing selection. These findings highlight the evolutionary pattern of the two gene families for allowing the fungus a rapid adaptation towards endophytism and facilitating diverse symbiotic interactions.
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