Comparative analyses of the Hymenoscyphus fraxineus and Hymenoscyphus albidus genomes reveals potentially adaptive differences in secondary metabolite and transposable element repertoires

BMC Genomics

Malin Elfstrand¹  Jun Chen¹  Jan Stenlid¹  Katarina Ihrmark¹  Kateryna Davydenko¹  Mikael Brandström Durling¹  Magnus Karlsson¹  Sandra Halecker²  Marc Stadler²  Michelle Cleary³ 

[1] Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences;Dept. Microbial Drugs, Helmholtz Centre for Infection Research;Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences;

关键词: Ash dieback;    Viridiol;    Fraxinus excelsior;    Transposable elements;    Secondary metabolites;    invasive species;   

DOI  :  10.1186/s12864-021-07837-2

来源: DOAJ

【 摘 要 】

Abstract Background The dieback epidemic decimating common ash (Fraxinus excelsior) in Europe is caused by the invasive fungus Hymenoscyphus fraxineus. In this study we analyzed the genomes of H. fraxineus and H. albidus, its native but, now essentially displaced, non-pathogenic sister species, and compared them with several other members of Helotiales. The focus of the analyses was to identify signals in the genome that may explain the rapid establishment of H. fraxineus and displacement of H. albidus. Results The genomes of H. fraxineus and H. albidus showed a high level of synteny and identity. The assembly of H. fraxineus is 13 Mb longer than that of H. albidus’, most of this difference can be attributed to higher dispersed repeat content (i.e. transposable elements [TEs]) in H. fraxineus. In general, TE families in H. fraxineus showed more signals of repeat-induced point mutations (RIP) than in H. albidus, especially in Long-terminal repeat (LTR)/Copia and LTR/Gypsy elements. Comparing gene family expansions and 1:1 orthologs, relatively few genes show signs of positive selection between species. However, several of those did appeared to be associated with secondary metabolite genes families, including gene families containing two of the genes in the H. fraxineus-specific, hymenosetin biosynthetic gene cluster (BGC). Conclusion The genomes of H. fraxineus and H. albidus show a high degree of synteny, and are rich in both TEs and BGCs, but the genomic signatures also indicated that H. albidus may be less well equipped to adapt and maintain its ecological niche in a rapidly changing environment.

【 授权许可】

Unknown