characterization of xenorhabdus (î³-proteobacteria) strains associated bacteria with the steinernema (nematoda: steinernematidae) isolates from iran

the gram-negative bacterium xenorhabdus is mutualistically associated with entomopathogenic nematode, steinernema. three bacterial strains were isolated from the entomopathogenic nematodes, steinernema glaseri (steiner) and s. carpocapsae (weiser), of the white grubs, polyphylla olivieri (laporte de castelnau) in iran. this study was focused on the characterization of the bacterial strains by using phenetic characters and 16s ribosomal rna gene sequence. this polyphasic approach led to the identification of all strains as xenorhabdus spp., separated as x. nematophila and x. poinarii. the phylogenetic relationship between iranian and global strains of xenorhabdus was analyzed and discussed. characterization of symbiotic bacteria associated with the entomopathogenic nematodes is a main step to the study of different aspects of this complex. these results provide new insights for the biodiversity of bacto-helminthic complex in iran.