Phylogeny of the Glomales: deciphering the past to understand the present

Summary The Glomales comprise more than 130 described species, presently classified in three families and five genera. Previous analysis of the sequence of the nuclear genes coding for the ribosornal small subunit rRNA (SSU) obtained from 12 isolates representing as many species generally corroborated the taxonomy based on morphological characters. As part of an ongoing effort to understand better the relationship between glomalean species, four new glomalean SSU sequences obtained in our laboratory are described, along with partial sequences from other laboratories. Using this enlarged dataset, a current phylogenetic tree of the Glomales was reconstructed. The dataset was also analysed to locate informative regions of the glomalean SSU that could be targeted by molecular ecologists studying the taxonomy, identification and ecology of arbuscular mycorrhizal fungi.