title: Intra-isolate genome variation in arbuscular mycorrhizal fungi persists in the transcriptome.
abstract: Arbuscular mycorrhizal fungi (AMF) are heterokaryotes with an unusual genetic makeup. Substantial genetic variation occurs among nuclei within a single mycelium or isolate. AMF reproduce through spores that contain varying fractions of this heterogeneous population of nuclei. It is not clear whether this genetic variation on the genome level actually contributes to the AMF phenotype. To investigate the extent to which polymorphisms in nuclear genes are transcribed, we analysed the intra-isolate genomic and cDNA sequence variation of two genes, the large subunit ribosomal RNA (LSU rDNA) of Glomus sp. DAOM-197198 (previously known as G. intraradices) and the POL1-like sequence (PLS) of Glomus etunicatum. For both genes, we find high sequence variation at the genome and transcriptome level. Reconstruction of LSU rDNA secondary structure shows that all variants are functional. Patterns of PLS sequence polymorphism indicate that there is one functional gene copy, PLS2, which is preferentially transcribed, and one gene copy, PLS1, which is a pseudogene. This is the first study that investigates AMF intra-isolate variation at the transcriptome level. In conclusion, it is possible that, in AMF, multiple nuclear genomes contribute to a single phenotype.
authors.affiliation: Département de Sciences Biologiques, Institut de Recherche en Biologie Végétale, Université de Montréal, Montréal, QC H1X 2B2, Canada. eva.boon@umontreal.ca
authors.forename: E
authors.initials: E
authors.lastname: Boon
authors.forename: E
authors.initials: E
authors.lastname: Zimmerman
authors.forename: B F
authors.initials: BF
authors.lastname: Lang
authors.forename: M
authors.initials: M
authors.lastname: Hijri
mesh_terms: D001483:Base Sequence; D004256:DNA Polymerase I / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D020869:Gene Expression Profiling; D014644:Genetic Variation; D016681:Genome, Fungal / Q000235:genetics*; D055137:Glomeromycota / Q000235:genetics*; D008969:Molecular Sequence Data; D038821:Mycorrhizae / Q000235:genetics*; D010641:Phenotype; D054658:Ribosome Subunits, Large / Q000235:genetics; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D004256:DNA Polymerase I