Molecular diversity of <italic>Photorhabdus</italic> and <italic>Xenorhabdus</italic> bacteria, symbionts of <italic>Heterorhabditis</italic> and <italic>Steinernema</italic> nematodes retrieved from soil in Benin.

The diversity of 43 bacterial strains isolated from Beninese entomopathogenic nematodes was investigated molecularly by analyzing the 16S rRNA, recA, and gyrB genes. Based on 16S rRNA sequence analysis, 15 bacterial strains were identified as <italic>Xenorhabdus</italic> sp., 27 strains as <italic>Photorhabdus</italic> sp., and one as <italic>Serratia</italic> sp. The <italic>Xenorhabdus</italic> strains were isolated from <italic>Steinernema</italic> nematodes and identified as <italic>Xenorhabdus indica</italic> based on 16S rRNA gene and concatenated recA and gyrB sequence analysis. However, analysis of 16S rRNA and concatenated recA and gyrB gene sequences of the <italic>Photorhabdus</italic> strains, all isolated from <italic>Heterorhabditis</italic> nematodes, resulted in two separate sub-clusters (A) and (B) within the <italic>Photorhabdus luminescens</italic> group, distinct from the existing subspecies. They share low sequence similarities with nearest phylogenetic neighbors <italic>Photorhabdus luminescens</italic> subsp. <italic>luminescens</italic> HbT, <italic>Photorhabdus luminescens</italic> subsp. <italic>caribbeanensis</italic> HG29T, and <italic>Photorhabdus luminescens</italic> subsp. <italic>noenieputensis</italic> AM7T. [ABSTRACT FROM AUTHOR]