Rhizorhabdus antheiae sp. nov. and Sphingomonas eleionomae sp. nov., new aerobic anoxygenic phototrophs isolated from a Manitoban marsh.

A peach-pigmented strain FW153T and a yellow-pigmented FW199T were isolated from marsh water located at Fort Whyte, Manitoba, Canada. Both produce an anoxygenic photosynthetic apparatus, with a reaction centre encircled by a light-harvesting I complex containing bacteriochlorophyll a. They do not produce RuBisCo and do not grow anaerobically or autotrophically, supporting the classification of both as aerobic anoxygenic phototrophs. Sequencing of the 16S rRNA gene showed similarity to Rhizorhabdus phycosphaerae (99.93%), Rhizorhabdus wittichii (98.73%) and Rhizorhabdus histidinilytica (98.52%) for FW153T, while for FW199T, it was Sphingomonas molluscorum (97.47%), Sphingomonas dokdonensis (97.44%) and Sphingomonas kyeonggiensis (97.08%). Polyphasic analysis identified differences in physiology and cellular fatty acid composition, as well as within the genome, with average nucleotide identity (<95%) and digital DNA-DNA hybridization values (<70%) between each strain and their closest relatives supporting species designation. Therefore, we propose that FW153T (=NCIMB 15610T=DSM 120042T) and FW199T (=NCIMB 15611T=DSM 120043T) be classified as the type strains of new species with the names Rhizorhabdus antheiae sp. nov. and Sphingomonas eleionomae sp. nov., respectively.