Proposal of Rhodoplanes tepidamans sp. nov. to accommodate the thermotolerant phototrophic bacterium previously...

Previously we proposed the reclassification of a thermotolerant phototrophic bacterium, 'Rhodopseudomonas cryptolactis' Stadtwald-Demchick et al. 1990, as 'Rhodoplanes cryptolactis' nom. rev., comb. nov. with strain DSM 9987T (ATCC 49414T) as the type strain. However, while both the names 'Rhodopseudomonas cryptolactis' and 'Rhodoplanes cryptolactis' have not been validated, strain ATCC 49414T is no longer available from the culture collection. This situation indicates that the taxonomic status of the bacterium with both the names to be validated has been lost. In this study, we re-examined the taxonomic characteristics of strain DSM 9987T (TUT3520T as our own collection number) compared with those of six species of the genus Rhodoplanes with validly published names. The results of 16S rRNA gene sequence comparisons indicated that TUT3520T had a 99.0 % level of similarity to the type strains of Rhodoplanes oryzae and Rhodoplanes elegans as its closest relatives and 98.9-96.2 % similarities to other species of the genus Rhodoplanes. Genomic DNA-DNA similarities between TUT3520T and the type strains of the species of the genus Rhodoplanes were less than 50 %. Results of phenotypic testing indicated that TUT3520T could be differentiated from any species of the genus Rhodoplanes by a combination of in vivo absorption spectra, growth temperature, vitamin requirements, carbon nutrition and some other characteristics. Thus, we propose Rhodoplanes tepidamans sp. nov. to accommodate the bacterium previously referred to as 'Rhodoplanes (Rhodopseudomonas) cryptolactis'. The type strain is strain TUT3520T (=DSM 9987T=NBRC 104267T).