Photorhabdus antumapuensis sp. nov., a novel symbiotic bacterial species associated with Heterorhabditis atacamensis entomopathogenic nematodes.

One motile, Gram-negative, non-spore-forming and rod-shaped symbiotic bacterium, strain UCH-936 ^T , was isolated from Heterorhabditis atacamensis nematodes. Results of biochemical, physiological, molecular and genomic analyses suggest that it represents a new species, which we propose to name Photorhabdus antumapuensis sp. nov. Digital DNA-DNA hybridization shows that strain UCH-936 ^T is more closely related to Photorhabdus kleinii DSM 23513 ^T , but shares solely 50.5 % similarity, which is below the 70% cut-off value that delimits species boundaries in bacteria. Phylogenetic reconstructions using whole-genome sequences show that strain UCH-936 ^T forms a unique clade, suggesting its novel and distinct taxonomic status again. Similarly, comparative genomic analyses shows that the virulence factor flagella-related gene fleR , the type IV pili-related gene pilL and the vibriobactin-related gene vibE are present in the genome of strain UCH-936 ^T but absent in the genomes of its closest relatives. Biochemically and physiologically, UCH-936 ^T differs also from all closely related Photorhabdus species. Therefore, Photorhabdus antumapuensis sp. nov. is proposed as a new species with the type strain UCH-936 ^T (CCCT 21.06 ^T =CCM 9188 ^T =CCOS 1991 ^T ).