Conspecificity of DAOM 197198, the model arbuscular mycorrhizal fungus, with Glomus irregulare: molecular evidence with three protein-encoding genes

Abstract

Ribosomal nuclear genes are routinely utilized in the molecular identification of fungi. The variation in the multiple copies of these genes within each Glomeromycota strain and species reduces their usefulness for molecular characterization of arbuscular mycorrhizal fungi. To explore the potential of molecular tools for the identification of Glomus species, a multi-gene analysis approach was undertaken. Three protein-encoding genes were tested, namely elogation factor 1-α (765 bp), V-H+-ATPase VHA5 (1468 bp), and F0F1-ATPase β-subunit (621 bp). The latter is newly reported for the Glomeromycetes. Eleven species, including the type-specimen of Glomus irregulare Blaszk., Wubet, Renker & Buscot, a reference strain of G. intraradices N.C. Schenck & G.S. Sm. (DAOM 225240), and five strains of Glomus sp. formerly identified as G. intraradices, were analysed. These genes did not show polymorphisms within strains, and results indicated a close relationship between molecular identification and morphological characterization. Species with closely related spore morphological features, G. aggregatum N.C. Schenck & G.S. Sm., G. diaphanum Morton & Walker, G. irregulare , and Glomus sp. DAOM 197198, showed more than 99% nucleotide similarity, while the morphologically distinct species, G. cerebriforme McGee, G. clarum T.H. Nicolson & N.C. Schenck, G. claroideum N.C. Schenck & G.S. Sm., G. custos C. Cano & Dalpé, G. mosseae (T.H. Nicolson & Gerd.) Gerd. & Trappe, and G. proliferum Dalpé & Declerck, showed less than 97% similarity for at least one gene. A 100% molecular similarity for all three genes was found between G. irregulare and Glomus sp. DAOM 197198, confirming the new identity of the model arbuscular mycorrhizal fungus. Similarity thresholds for identification by DNA sequencing are discussed.

Phosphorus acquisition efficiency in arbuscular mycorrhizal maize is correlated with the abundance of root-external hyphae and the accumulation of transcripts encoding PHT1 phosphate transporters

“…Samples were prepared using irregularis elongation factor gene (Sokolski et al, 2010). Statistical analysis was conducted…”

Lipid content disturbance in the arbuscular mycorrhizal, Glomus irregulare grown in monoxenic conditions under PAHs pollution

“…The AM fungus used was Glomus sp. DAOM 197198 formerly identified as Glomus intraradices Schenck and Smith and presently reclassified in a clade that contains the recently described species G. irregulare Blaszk., Wubet, Renker and Buscot (Blaszkowski et al 2008;Stockinger et al 2009;Sokolski et al 2010).…”

Phosphate Transporter Genes as Reliable Gene Markers for the Identification and Discrimination of Arbuscular Mycorrhizal Fungi in the Genus Glomus

“…We sequenced an 852-bp fragment from the coding region of a transmembrane phosphate transporter gene (14) of 25 Glomus strains (Table 1) from the Canadian in vitro and in vivo Glomeromycota collection. In vitro strains were propagated on Ri T-DNA-transformed carrot (Daucus carota) roots on M medium (12), and in vivo strains of Glomus mosseae and G. coronatum were pot cultured on Allium porrum (30). Total DNA was extracted from spores using the FastDNA kit (Qbiogene Inc.).…”

“…The two latter strains are also morphologically identical. Consequently, strains 2 to 11, including the arbuscular mycorrhizal model fungus DAOM197198 (30), should all be considered to be G. irregulare. The original G. intraradices (KS906, strain 14) is clearly distinct from all the other species studied, particularly the isolate DAOM197198, confirming the results of Stockinger et al (31).…”