Two-speed genomes of Epichloe fungal pathogens show contrasting signatures of selection between species and across populations
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Date
2024-02Type
- Journal Article
ETH Bibliography
yes
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Abstract
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. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000649622Publication status
publishedExternal links
Journal / series
Molecular EcologyVolume
Pages / Article No.
Publisher
Wiley-BlackwellSubject
effector genes; fungal pathogen; genome compartmentalization; genome scan; population genomics; selective sweepOrganisational unit
03516 - McDonald, Bruce / McDonald, Bruce
08670 - Gruppe Biosystematik und Sammlungen
Funding
169269 - Molecular host adaptation of Epichloë endophytes (SNF)
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ETH Bibliography
yes
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