Population genomics reveals that within-fungus polymorphism is common and maintained in populations of the mycorrhizal fungus Rhizophagus irregularis.

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Etat: Public
Version: Final published version
ID Serval
serval:BIB_39388D2C3198
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Population genomics reveals that within-fungus polymorphism is common and maintained in populations of the mycorrhizal fungus Rhizophagus irregularis.
Périodique
The ISME Journal
Auteur(s)
Wyss T., Masclaux F.G., Rosikiewicz P., Pagni M., Sanders I.R.
ISSN
1751-7362 (Print)
ISSN-L
1751-7362
Statut éditorial
Publié
Date de publication
2016
Peer-reviewed
Oui
Volume
10
Numéro
10
Pages
2514-2526
Langue
anglais
Résumé
Arbuscular mycorrhizal (AM) fungi are symbionts of most plants, increasing plant growth and diversity. The model AM fungus Rhizophagus irregularis (isolate DAOM 197198) exhibits low within-fungus polymorphism. In contrast, another study reported high within-fungus variability. Experiments with other R. irregularis isolates suggest that within-fungus genetic variation can affect the fungal phenotype and plant growth, highlighting the biological importance of such variation. We investigated whether there is evidence of differing levels of within-fungus polymorphism in an R. irregularis population. We genotyped 20 isolates using restriction site-associated DNA sequencing and developed novel approaches for characterizing polymorphism among haploid nuclei. All isolates exhibited higher within-isolate poly-allelic single-nucleotide polymorphism (SNP) densities than DAOM 197198 in repeated and non-repeated sites mapped to the reference genome. Poly-allelic SNPs were independently confirmed. Allele frequencies within isolates deviated from diploids or tetraploids, or that expected for a strict dikaryote. Phylogeny based on poly-allelic sites was robust and mirrored the standard phylogeny. This indicates that within-fungus genetic variation is maintained in AM fungal populations. Our results predict a heterokaryotic state in the population, considerable differences in copy number variation among isolates and divergence among the copies, or aneuploidy in some isolates. The variation may be a combination of all of these hypotheses. Within-isolate genetic variation in R. irregularis leads to large differences in plant growth. Therefore, characterizing genomic variation within AM fungal populations is of major ecological importance.

Pubmed
Web of science
Open Access
Oui
Création de la notice
27/01/2016 21:57
Dernière modification de la notice
20/08/2019 13:28
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