Use of fatty acids for identification of AM fungi and estimation of the biomass of AM spores in soil

Fatty acid methyl ester (FAME) analysis performed on the spores of four arbuscular mycorrhizal (AM) fungi (Glomus coronatum, Glomus mosseae, Gigaspora margarita and Scutellospora calospora) showed 16:1ω5c to be the dominant fatty acid present. In addition, spores of Gi. margarita contained large quantities of 18:1ω9c and three 20-C fatty acids (20:1ω9c, 20:2ω6c and 22:1ω9c) that were not present in the spores of the other two species. Addition of a known number of spores of each AM species to soil demonstrated that the spore fatty acids could be readily detected and quantified against the background of soil fatty acids. Addition of different combinations and quantities of spores to soil gave the expected ratios of the marker fatty acids in the soil FAME profiles. The results confirm the use of 16:1ω5c as a marker fatty acid for AM fungi in controlled environments and suggest that 18:1ω9c, 20:1ω9c, 20:2ω6c and 22:1ω9c could be used as possible markers for the detection of Gi. margarita.