Tistlia consotensis gen. nov., sp. nov., an aerobic, chemoheterotrophic, free-living, nitrogen-fixing alphaproteobacterium, isolated from a Colombian saline spring

Abstract

A Gram-negative, aerobic, mesophilic, non-spore-forming, chemotrophic, chlorophyll-lacking, nitrogen-fixing bacterium, designated strain USBA 355T, was isolated from the saline spring ‘Salado de Consotá’ situated in the Colombian Andes. The non-flagellated cells of strain USBA 355T were straight to slightly curved rods (0.6–0.7 × 3.0–3.5 μm). Growth occurred optimally at 30 °C (growth temperature range between 20 and 40 °C), at pH 6.5–6.7 (pH growth range between 5.0 and 8.0) and at 0.5 % NaCl (w/v) (range between 0 and 4 %). The major quinone present was Q-10 and the predominant fatty acids identified were C19 : 0 cyclo ω8c, C18 : 1 ω7c and C18 : 0. The G+C content of the chromosomal DNA was 71±1 mol%. 16S rRNA gene sequence analysis indicated that strain USBA 355T formed a distant phylogenetic line of descent with members of the genus Thalassobaculum, family Rhodospirillaceae, class Alphaproteobacteria (90 % gene sequence similarity). Comparison of the phylogenetic, chemotaxonomic and physiological features of strain USBA 355T with all other members of the family Rhodospirillaceae suggested that it represents a novel genus and species for which the name Tistlia consotensis gen. nov., sp. nov. is proposed. The type strain of the type species is USBA 355T (=JCM 15529T=KCTC 22406T).