title: Extreme diversification of the mating type-high-mobility group (MATA-HMG) gene family in a plant-associated arbuscular mycorrhizal fungus.
abstract: Arbuscular mycorrhizal fungi (AMF) are important plant symbionts that have long been considered evolutionary anomalies because of their apparent long-term lack of sexuality, but recent explorations of available DNA sequence have challenged this notion by revealing the presence of homologues of fungal mating type-high-mobility group (MATA-HMG) and core meiotic genes in these organisms. To obtain more insights into the sexual potential of AMF, homologues of MATA-HMGs were sought in the transcriptome of three AMF isolates, and their functional and evolutionary trajectories were studied in genetically divergent strains of Rhizophagus irregularis using conventional and quantitative PCR procedures. Our analyses revealed the presence of at least 76 homologues of MATA-HMGs in R. irregularis isolates. None of these was found to be surrounded by genes generally found near other known fungal mating type loci, but here we report the presence of a 9-kb-long region in the AMF R. irregularis harbouring a total of four tandem-repeated MATA-HMGs; a feature that highlights a potentially elevated intragenomic diversity in this AMF species. The present study provides intriguing insights into the genome evolution of R. irregularis, and represents a stepping stone for understanding the potential of these fungi to undergo cryptic sex.
authors.affiliation: Canadian Institute for Advanced Research, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
authors.forename: Rohan
authors.initials: R
authors.lastname: Riley
authors.affiliation: Canadian Institute for Advanced Research, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
authors.forename: Philippe
authors.initials: P
authors.lastname: Charron
authors.affiliation: Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Idnurm
authors.affiliation: FASTERIS S.A., Ch. du Pont-du-Centenaire 109, PO Box 28, CH-1228, Plan-les-Ouates, Switzerland.
authors.forename: Laurent
authors.initials: L
authors.lastname: Farinelli
authors.affiliation: Agriculture and Agri-Food Canada, 960 Carling Ave., Ottawa, ON, K1A 0C6, Canada.
authors.forename: Yolande
authors.initials: Y
authors.lastname: Dalpé
authors.affiliation: UMR INRA-UHP 'Interaction Arbres/Micro-Organismes', Centre INRA de Nancy, Champenoux, France.
authors.forename: Francis
authors.initials: F
authors.lastname: Martin
authors.affiliation: Canadian Institute for Advanced Research, Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Corradi
mesh_terms: D004271:DNA, Fungal; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D049770:Genes, Mating Type, Fungal; D016681:Genome, Fungal; D055137:Glomeromycota / Q000235:genetics* / Q000378:metabolism; D006609:High Mobility Group Proteins / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D038821:Mycorrhizae / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D012098:Reproduction; D020080:Tandem Repeat Sequences; D059467:Transcriptome
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D006609:High Mobility Group Proteins
keywords: ancient asexuals; arbuscular mycorrhizal fungi (AMF); heterokaryosis; high-mobility group proteins; mating; paralogy; recombination
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