Pseudomonas soli sp. nov., a novel producer of xantholysin congeners

A chemoorganotrophic Gram-negative bacterium was isolated by means of a diffusion sandwich system from a soil sample from the Sierra Nevada National Park, Spain. Strain F-279,208^T was oxidase and catalase positive, strictly aerobic, non-spore-forming and motile by single polar flagellum. Phylogenetic analysis of the 16S rRNA, gyrB, rpoB and rpoD genes revealed that strain F-279,208^T belongs to the Pseudomonas putida group with Pseudomonas mosselii and Pseudomonas entomophila as its closest relatives. DNA–DNA hybridization assays and phenotypic traits confirmed that this strain belongs to a novel species of the genus Pseudomonas, for which the name Pseudomonas soli sp. nov. is proposed. The type strain is F-279,208^T (=DSM 28043^T = LMG 27941^T), and during fermentation it produces xantholysins, a family of lipodepsipeptides. The major compound, xantholysin A, showed an interesting activity in a RCC4 kidney tumor cell line with inactivation of VHL linked with the HIF pathway, without any cytotoxic effects against other human tumor cell lines tested including, liver, pancreas and breast.