Molecular diversity of glomalean (arbuscular mycorrhizal) fungi determinedas distinct Glomus specific DNA sequences from roots of field grown peas

The molecular diversity of glomalean fungi was studied by analysis of Glomu s specific sequences amplified from field harvested peas. Glomus specific, large rDNA sequences were amplified from roots in a nested PCR reaction, fo llowing primary amplification with eukaryote specific primers. The nested p rimers were designed to amplify a lineage within the genus Glomus including G. mosseae, G. caledonium and G. geosporum, all of which had repeatedly be en isolated from trap cultures set up with soil from the field. Single-stra nded conformation polymorphism (SSCP) was used to screen the nested FCR pro ducts for presence of multiple sequence types. Nested PCR products were seq uenced if necessary after reamplification of single SSCP types. The root de rived sequences were aligned with sequences from spores of 17 cultured Glom us isolates; five of these isolated from the same field from where the peas were harvested. Some of the root-derived sequences were from lineages othe r than those species isolated from the field and some of the isolated speci es were not retrieved as sequences from the roots.