title: Comparative genomics of the pine pathogens and beetle symbionts in the genus Grosmannia.
abstract: Studies on beetle/tree fungal symbionts typically characterize the ecological and geographic distributions of the fungal populations. There is limited understanding of the genome-wide evolutionary processes that act within and between species as such fungi adapt to different environments, leading to physiological differences and reproductive isolation. Here, we assess genomic evidence for such evolutionary processes by extending our recent work on Grosmannia clavigera, which is vectored by the mountain pine beetle and jeffrey pine beetle. We report the genome sequences of an additional 11 G. clavigera (Gc) sensu lato strains from the two known sibling species, Grosmannia sp. (Gs) and Gc. The 12 fungal genomes are structurally similar, showing large-scale synteny within and between species. We identified 103,430 single-nucleotide variations that separated the Grosmannia strains into divergent Gs and Gc clades, and further divided each of these clades into two subclades, one of which may represent an additional species. Comparing variable genes between these lineages, we identified truncated genes and potential pseudogenes, as well as seven genes that show evidence of positive selection. As these variable genes are involved in secondary metabolism and in detoxifying or utilizing host-tree defense chemicals (e.g., polyketide synthases, oxidoreductases, and mono-oxygenases), their variants may reflect adaptation to the specific chemistries of the host trees Pinus contorta, P. ponderosa, and P. jeffreyi. This work provides a comprehensive resource for developing informative markers for landscape population genomics of these ecologically and economically important fungi, and an approach that could be extended to other beetle-tree-associated fungi.
authors.affiliation: Department of Wood Science, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Massoumi Alamouti
authors.affiliation: Department of Wood Science, University of British Columbia, Vancouver, British Columbia, CanadaDOE Joint Genome Institute, Walnut Creek, California.
authors.forename: Sajeet
authors.initials: S
authors.lastname: Haridas
authors.affiliation: Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Feau
authors.affiliation: British Columbia Cancer Agency Genome Sciences Centre, Vancouver, British Columbia, Canada.
authors.forename: Gordon
authors.initials: G
authors.lastname: Robertson
authors.affiliation: Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, CanadaMichael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Jörg
authors.initials: J
authors.lastname: Bohlmann
authors.affiliation: Department of Wood Science, University of British Columbia, Vancouver, British Columbia, Canada Colette.Breuil@ubc.ca.
authors.forename: Colette
authors.initials: C
authors.lastname: Breuil
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000382:microbiology*; D014644:Genetic Variation; D016681:Genome, Fungal; D023281:Genomics; D058507:Host Specificity; D055155:Ophiostomatales / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D028223:Pinus / Q000382:microbiology*; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic; D013559:Symbiosis
keywords: beetle; fungi; genomics; pathogen; pine; symbiont