Molecular characterisation of entomopathogenic nematodes isolated in Italy by PCR-RFLP analysis of the ITS region of the ribosomal DNA repeat unit

摘要

The ITS region of 44 Italian strains of entomopathogenic nematodes (EPNs) belonging to two species isolated during the last ten years in southern Italy was amplified by PCR and the resulting products were digested with nine different enzymes; the fragments generated were then separated by agarose gel electrophoresis. The strains were previously identified by morphological examination using morphometric data. For many of the strains, RFLP analysis confirmed morphological identification (as Steinernema feltiae and Heterorhabditis bacteriophora) but, for some, RFLP analysis revealed differences when compared with the results from morphometric examinations. In particular, the RFLP profiles of three strains from Sardinia showed differences when compared to the profiles of S. feltiae and H. bacteriophora and were the same as that of Steinernema litorale, which until now has only been found in Japan. We tried to interbreed the Sardinian strains with S. litorale and S. feltiae; mating attemps were observed but no progeny resulted. The symbiotic bacteria of Sardinian strains belong to the species Xenorhabdus bovienii.