Falsirhodobacter halotolerans gen. nov., sp. nov., isolated from dry soils of a solar saltern

Abstract

Two bacterial strains (JA744T and JA745) were isolated from dry soil samples collected from solar salterns at Humma, Odisha, India. Both strains were Gram-stain-negative, catalase- and oxidase-positive, motile rods. Major fatty acids in both strains included C18 : 1ω7c, C18 : 0 and C16 : 0, while minor amounts of C10 : 0 3-OH, C12 : 0, C12 : 0 3-OH, C14 : 0 and C16 : 0 were also present. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol, an unidentified glycolipid, five unidentified lipids, an unidentified aminolipid and an unidentified phospholipid made up the polar lipids of both strains. Both strains had bacteriohopane derivatives (BHD1,2) and diploptene as major hopanoids. Mean genomic DNA G+C content was 75±1 mol% and the two strains were closely related (mean DNA–DNA hybridization >90 %). Phylogenetic analysis based on the 16S rRNA gene sequence showed that the two strains clustered with species of the genus Rhodobacter belonging to the family Rhodobacteraceae of the class Alphaproteobacteria . The highest sequence similarity was observed with Rhodobacter sphaeroides ATH2.4.1T (96 %) and other members of the genera Rhodobacter and Pseudorhodobacter (<96 %). However, the two strains were positioned distinctly outside the group formed by the other genera of the family Rhodobacteraceae . Distinct morphological, physiological and genotypic differences from previously described taxa support the classification of these isolates as representatives of a novel species in a new genus, for which the name Falsirhodobacter halotolerans gen. nov., sp. nov. is proposed. The type strain of Falsirhodobacter halotolerans is JA744T ( = KCTC 32158T  = NBRC 108897T).