Caballeronia mineralivorans sp. nov., isolated from oak-Scleroderma citrinum mycorrhizosphere

Six bacterial strains were isolated from the oak-Scleroderma citrinum ectomycorrhizosphere in acidic and nutrient-poor forest soil for their high efficacy to weather minerals. Four of the six isolates, PML1(12)T and PML1(4), PML1(14) and PML1(16), were further characterized extensively. They were Gram negative, obligate aerobic, motile, non spore forming and rod-shaped. The major fatty acids of strain PML1(12)T were cyclo-C17:0, cyclo-C19:0-ω8c, C16:0 and C18:1-ω7c. The GC content of the DNA was 60.8%. The 16S rRNA and GyrB analyses showed that the four PML strains formed a distinct phylogenetic lineage within the genus Caballeronia, most closely related to Caballeronia udeis. This result was confirmed by whole-genome phylogeny analyses done on strain PML1(12)T. The results of digital DNA-DNA relatedness further supported the separation of the new isolates from closely related species. Morphological, chemotaxonomic properties were also consistent with the description of the genus Caballeronia. It is therefore proposed that strains PML1(12)T and PML1(4), PML1(14) and PML1(16) be recognized as a novel species, for which the name Caballeronia mineralivorans sp. nov. is proposed. The type strain is PML1(12)T (= DSM 104028 and LMG 2991).