Ktedonosporobacter rubrisoli gen. nov., sp. nov., a novel representative of the class Ktedonobacteria, isolated from red soil, and proposal of Ktedonosporobacteraceae fam. nov.

A novel filamentous, spore-forming, Gram-stain-positive bacterium, designated SCAWS-G2T, was isolated from red soil in Jiangxi Province, PR China. The strain grew at 25-45 °C and at pH 4.0-7.0, and was able to tolerate up to 50 mM Zn2+. The complete genome of strain SCAWS-G2T was a circular chromosome of ~11.34 Mb, which contained four 16S rRNA genes with three sequence types (0.4-0.8 % differences). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SCAWS-G2T formed a distinct lineage within the order Ktedonobacterales, showing <89.2 % sequence similarities to the recognized taxa of this order. The whole-genome based phylogenomic tree separated strain SCAWS-G2T from the recognized families within Ktedonobacterales. The genome-wide average nucleotide identity values between strain SCAWS-G2T and the related type strains were <68.2 %. The strain can also be differentiated from the recognized families by a number of phenotypic characteristics. The polar lipids of SCAWS-G2T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, seven unidentified glycolipids and one unidentified lipid. The peptidoglycan amino acids contained ornithine, glycine, glutamic acid and alanine, and the cell-wall sugars were mainly galactose and rhamnose. The major fatty acids were C16 : 1 2-OH, C16 : 0 and iso-C17 : 0. Based on all these data, we propose that strain SCAWS-G2T represents a novel genus and species, Ktedonosporobacter rubrisoli gen. nov., sp. nov., within the new family Ktedonosporobacteraceae fam. nov. of the order Ktedonobacterales. The type strain of Ktedonosporobacter rubrisoli is SCAWS-G2T (=CGMCC 1.16132T=DSM 105258T).