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Comparative Genomics of the Pine Pathogens and Beetle Symbionts in the Genus Grosmannia
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- Author(s) / Creator(s)
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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 singlenucleotide
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. -
- Date created
- 2014-01-01
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- Type of Item
- Article (Published)