Descriptions of Rhodopseudomonas parapalustris sp. nov., Rhodopseudomonas harwoodiae sp. nov. and Rhodopseudomonas pseudopalustris sp. nov., and emended description of Rhodopseudomonas palustris

Abstract

Four strains (JA310T, JA531T, JA447 and JA490) of red to reddish brown pigmented, rod-shaped, motile and budding phototrophic bacteria were isolated from soil and freshwater sediment samples from different geographical regions of India. All strains contained bacteriochlorophyll a and carotenoids of the spirilloxanthin series. The major cellular fatty acid of strains JA310T and JA531T was C18 : 1ω7c, the quinone was Q-10 and polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, an aminohopanoid and an unidentified aminolipid. Phylogenetic analysis based on 16S rRNA gene sequences showed that all strains clustered with species of the genus Rhodopseudomonas in the class Alphaproteobacteria . Strains JA531T, JA447 and JA490 were genotypically (>80 % related based on DNA–DNA hybridization) and phenotypically closely related to each other and the three strains were distinct from strain JA310T (33 % related). Furthermore, all four strains had less than 48 % relatedness (DNA–DNA hybridization) with type strains of members of the genus Rhodopseudomonas , i.e. Rhodopseudomonas palustris ATCC 17001T, Rhodopseudomonas faecalis JCM 11668T and Rhodopseudomonas rhenobacensis DSM 12706T. The genomic DNA G+C contents of strains JA310T and JA531T were 63.8 and 62.4 mol%, respectively. On the basis of phenotypic, chemotaxonomic and molecular genetic evidence, it is proposed that strains JA310T ( = NBRC 106083T = KCTC 5839T) and JA531T ( = NBRC 107575T = KCTC 5841T) be classified as the type strains of two novel species of the genus Rhodopseudomonas , Rhodopseudomonas parapalustris sp. nov. and Rhodopseudomonas harwoodiae sp. nov., respectively. In addition, we propose that strain DSM 123T ( = NBRC 100419T) represents a novel species, Rhodopseudomonas pseudopalustris sp. nov., since this strain differs genotypically and phenotypically from R. palustris ATCC 17001T and other members of the genus Rhodopseudomonas . An emended description of R. palustris is also provided.