Evidence for the sexual origin of heterokaryosis in arbuscular mycorrhizal fungi

0464259 - BÚ 2017 RIV GB eng J - Journal Article
Ropars, J. - Sedzielewska Toro, K. - Noel, J. - Pelin, A. - Charron, P. - Farinelli, L. - Marton, T. - Krüger, Manuela - Fuchs, J. - Brachmann, A. - Corradi, N.
Evidence for the sexual origin of heterokaryosis in arbuscular mycorrhizal fungi.
Nature Microbiology. Roč. 1, č. 6 (2016), s. 1-9, č. článku 16033. ISSN 2058-5276. E-ISSN 2058-5276
R&D Projects: GA MŠMT(CZ) EE2.3.30.0048
Institutional support: RVO:67985939
Keywords : arbuscular mycorhiza * population genetics * evolutionary genetics
Subject RIV: EB - Genetics ; Molecular Biology

Sexual reproduction is ubiquitous among eukaryotes, and fully asexual lineages are extremely rare. Prominent among ancient asexual lineages are the arbuscular mycorrhizal fungi (AMF), a group of plant symbionts with a multinucleate cytoplasm. Genomic divergence among co-existing nuclei was proposed to drive the evolutionary success of AMF in the absence of sex(1), but this hypothesis has been contradicted by recent genome analyses that failed to find significant genetic diversity within an AMF isolate(2,3). Here, we set out to resolve issues surrounding the genome organization and sexual potential of AMF by exploring the genomes of five isolates of Rhizophagus irregularis, a model AMF. We find that genetic diversity in this species varies among isolates and is structured in a homo-dikaryonlike manner usually linked with the existence of a sexual life cycle. We also identify a putative AMF mating-type locus, containing two genes with structural and evolutionary similarities with the mating-type locus of some Dikarya. Our analyses suggest that this locus may be multi-allelic and that AMF could be heterothallic and bipolar. These findings reconcile opposing views on the genome organization of these ubiquitous plant symbionts and open avenues for strain improvement and environmental application of these organisms.
Permanent Link: http://hdl.handle.net/11104/0265218