sp. nov. and sp. nov., Pink-Pigmented Bacteria Isolated from Root Nodules of (Retz.) Poir.

Four pigment-producing rhizobial strains nodulating (Retz.) Poir. formed a unique group in genus in the phylogeny of a 16S rRNA gene and five housekeeping genes (, , , , and ) in a genome analysis, phenotypic characteristics analysis, and chemotaxonomic analysis. These four strains shared as high as 99.3% similarity with LmiM8 in the 16S rRNA gene sequence and, in an MLSA, were subdivided into two clusters, ANI (genome average nucleotide) and dDDH (digital DNA-DNA hybridization) which shared sequence similarities lower than the species thresholds with each other and with the reference strains for related species. The polar lipids elucidated that phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), and cardiolipin were the main components for strain SWF67558 and for strain HBU65207, with the exception of PC. SWF67558 and HBU65207 strains had similar predominant cellular fatty acids, including C16:0, C18:0, summed feature 2, and summed feature8, but with different contents. In addition, all the four novel strains produced pink-pigment, and the main coloring material extract from strain SWF67558 was identified as zeaxanthin, which presented antioxidant ability and reduction power. With all the phylogenetic and phenotypic divergency, we proposed these pink-pigmented symbiotic bacteria as two novel species, named sp. nov. and sp. nov., with SWF67558 (=KCTC82331=GDMCC1.2024) and HBU65207 (=KCTC92125=GDMCC1.2023) as the type strains, respectively.