title: Detection of a transient mitochondrial DNA heteroplasmy in the progeny of crossed genetically divergent isolates of arbuscular mycorrhizal fungi.
abstract: Nonself fusion and nuclear genetic exchange have been documented in arbuscular mycorrhizal fungi (AMF), particularly in Rhizophagus irregularis. However, mitochondrial transmission accompanying nonself fusion of genetically divergent isolates remains unknown. Here, we tested the hypothesis that mitochondrial DNA (mtDNA) heteroplasmy occurs in the progeny of spores, obtained by crossing genetically divergent mtDNAs in R. irregularis isolates. Three isolates of geographically distant locations were used to investigate nonself fusions and mtDNA transmission to the progeny. We sequenced two additional mtDNAs of two R. irregularis isolates and developed isolate-specific size-variable markers in intergenic regions of these isolates and those of DAOM-197198. We achieved three crossing combinations in pre-symbiotic and symbiotic phases. Progeny spores per crossing combination were genotyped using isolate-specific markers. We found evidence that nonself recognition occurs between isolates originating from different continents both in pre-symbiotic and symbiotic phases. Genotyping patterns of individual spores from the progeny clearly showed the presence of markers of the two parental mtDNA haplotypes. Our results demonstrate that mtDNA heteroplasmy occurs in the progeny of the crossed isolates. However, this heteroplasmy appears to be a transient stage because all the live progeny spores that were able to germinate showed only one mtDNA haplotype.
authors.affiliation: Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada.
authors.forename: Ivan Enrique
authors.initials: IE
authors.lastname: de la Providencia
authors.affiliation: Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada.
authors.forename: Maryam
authors.initials: M
authors.lastname: Nadimi
authors.affiliation: Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada.
authors.forename: Denis
authors.initials: D
authors.lastname: Beaudet
authors.affiliation: Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Rodriguez Morales
authors.affiliation: Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, H1X 2B2, Canada.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hijri
mesh_terms: D003433:Crosses, Genetic; D004272:DNA, Mitochondrial; D005838:Genotype; D055137:Glomeromycota / Q000235:genetics*; D006239:Haplotypes; D038821:Mycorrhizae / Q000235:genetics*; D013172:Spores, Fungal / Q000235:genetics*; D013559:Symbiosis
chemical_list: D004272:DNA, Mitochondrial
keywords: anastomosis; arbuscular mycorrhizal fungi (AMF); heteroplasmy; mitochondrial genome; nonself fusion; specific molecular marker