Assessment of genetic variability in populations of Nacobbus aberrans (Thorne, 1935) Thorne & Allen, 1944 (Nematoda: Pratylenchidae) from Argentina

Abstract

AbstractNacobbus aberrans produces severe damage to agriculture and is considered to be of quarantine importance. The levels of polymorphism and genetic differentiation among Argentine populations of this species from different hosts and origin were studied using Inter-Simple Sequence Repeat (ISSR) as molecular markers. Second-stage juveniles from nine populations associated with three different hosts (tomato, quinoa and potato) were analysed individually. Three primers were selected because they produced clear and 100% reproducible patterns; 37 fragments were considered for the analysis. The technique employed revealed high levels of polymorphisms, the highest proportion of genetic diversity being found within populations (95%). Populations showed a tendency to group together according to their original host, based on their pairwise FST. Low levels of genetic differentiation among populations were observed, suggesting an extensive gene flow among them. Passive dispersal of nematodes by natural means and anthropogenic activities would probably be, at least partially, responsible for the results observed. This work is the first study of genetic structure of N. aberrans populations at a macrogeographical level using ISSR markers.