Identification of Plant-Parasitic Nematodes Using FAME Analysis

Fatty acid methyl ester (FAME) analysis has been utilized to identify bacteria and some fungi, but little progress has been made to identify nematodes using this system. A series of samples containing varying numbers of individuals of Meloidogyne incognita, Rotylenchulus reniformis, and Heterodera glycines was used to determine the applicability of FAME analysis for identification of these three nematode species, quantify the minimum number of individuals required for identification, identify samples containing mixed-species populations, and evaluate the impact of plant host species on nematode fatty acid profiles. All three nematode genera were correctly identified with unique FAME profiles. A minimum of 100 vermiform stage nematodes was required for accurate identification of M. incognita, and R. reniformis while 25 cysts were required to identify H. glycines. Different ratios of mixed-species samples of M. incognita and R. reniformis could be identified with greater than 83% accuracy. Fatty acid profiles of M. incognita and R. reniformis varied significantly (P < 0.0001) when grown on each of three different host plants, though the increased variation within the two species did not inhibit identification of either species. By