Two-speed genomes of Epichloe fungal pathogens show contrasting signatures of selection between species and across populations.

Autor: Treindl AD; Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland.; Biodiversity and Conservation Biology, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland., Stapley J; Plant Pathology Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland., Croll D; Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland., Leuchtmann A; Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zurich, Zurich, Switzerland.
Jazyk: angličtina
Zdroj: Molecular ecology [Mol Ecol] 2024 Feb; Vol. 33 (4), pp. e17242. Date of Electronic Publication: 2023 Dec 12.
DOI: 10.1111/mec.17242
Abstrakt: Antagonistic selection between pathogens and their hosts can drive rapid evolutionary change and leave distinct molecular footprints of past and ongoing selection in the genomes of the interacting species. Despite an increasing availability of tools able to identify signatures of selection, the genetic mechanisms underlying coevolutionary interactions and the specific genes involved are still poorly understood, especially in heterogeneous natural environments. We searched the genomes of two species of Epichloe plant pathogen for evidence of recent selection. The Epichloe genus includes highly host-specific species that can sterilize their grass hosts. We performed selection scans using genome-wide SNP data from seven natural populations of two co-occurring Epichloe sibling species specialized on different hosts. We found evidence of recent (and ongoing) selective sweeps across the genome in both species. However, selective sweeps were more abundant in the species with a larger effective population size. Sweep regions often overlapped with highly polymorphic AT-rich regions supporting the role of these genome compartments in adaptive evolution. Although most loci under selection were specific to individual populations, we could also identify several candidate genes targeted by selection in sweep regions shared among populations. The genes encoded small secreted proteins typical of fungal effectors and cell wall-degrading enzymes. By investigating the genomic signatures of selection across multiple populations and species, this study contributes to our understanding of complex adaptive processes in natural plant pathogen systems.
(© 2023 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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