Molecular characterization of cyst nematode species (Heterodera spp.) from the Mediterranean basin using RFLPs and sequences of ITS-rDNA.

Fifteen populations of cyst-forming nematodes belonging to 11 known and one unidentified species collected in countries bordering the Mediterranean Sea were studied using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) and internal transcribed spacer (ITS)-rDNA sequences. RFLP profiles generated by the restriction enzymes AluI, AvaI, Bsh1236I, HaeIII, Hin6I, MvaI, PstI and RsaI are presented for Heterodera carotae, H. ciceri, H. fici, H. filipjevi, H. goettingiana, H. hordecalis, H. humuli, H. mediterranea, H. ripae and H. schachtii. Molecular data support the first detection of H. filipjevi from wheat in Italy and H. ripae from nettle in Greece. A relative high level of sequence divergence between populations of H. hordecalis was observed. This suggests that two species might presently be grouped under this taxon. The phylogenetic relationship between the Mediterranean cyst-forming nematode species is analysed based on the ITS-rDNA sequences.