Discrimination of Gigaspora species by PCR specific primers and phylogenetic analysis

Species of arbuscular mycorrhizal fungi (AMF) are usually identified by the morphological characteristics of their spores. However, considering the difficulties in diagnosing their taxa, the construction of species-specific primers has been proposed as an identification alternative. In this paper the problem of distinguishing different Gigaspora species with slight morphological differences was solved using species-specific primers and SSU and LSU rDNA sequence analyses of 18 AM fungal isolates comprising seven species. Neighbor joining, maximum parsimony, and maximum likelihood analyses were performed to evaluate the phylogenetic affiliation of the isolates, and a new reverse PCR primer (ALB1) specific for Gigaspora albida was designed and tested with 11 Gigaspora isolates (four species). The results confirmed misidentification of 'G. albida' FL 927 and 'G. margarita' BR 444 and supported referring FL 927 to G. rosea and BR 444 to G. albida.