Litchfieldia stipae sp. nov., a novel plant growth-promoting potential bacterium, isolated from the rhizosphere soil of Stipa breviflora in Inner Mongolia, China.

A novel Gram stain-positive, endospore-forming, motile, rod-shaped, aerobic bacterial strain, designated PS06T, was isolated from the rhizosphere soil of Stipa breviflora at the Siziwang Banner Research Station in Inner Mongolia, PR China. The strain could grow at 4-40 ℃ (optimum, 37 ℃), at pH 6.0-9.5 (optimum, pH 8.5), and in the presence of 0-5% NaCl (optimum, 1%). The phylogenetic analysis based on 16S rRNA gene sequences indicated that strain PS06T was most closely related to Litchfieldia salsus IBRC-M 10078T (16S rRNA similarity, 97.73%) and L. alkalitelluris DSM 16976T (97.65%) and formed an independent clade with these two type species in the genus Litchfieldia. The genome analysis showed that the average nucleotide identity (ANI) values and digital DNA-DNA hybridization (dDDH) of strain PS06T with L. salsus IBRC-M 10078T and L. alkalitelluris DSM 16976T were 78.0 and 76.1%, and 21.5 and 22.1%, respectively, which were significantly lower than the thresholds of 95% for ANI and 70% for dDDH for species delineation. The predominant cellular fatty acids (> 10%) were anteiso-C15:0 and iso-C15:0. The major polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and five unknown lipids. The genomic G + C content of strain PS06T was 37 mol%. Based on the phenotypic, genotypic, chemotaxonomic, and phylogenetic analyses, strain PS06T was classified as a novel species of the genus Litchfieldia, and the species name proposed was L. stipae sp. nov. The type strain of the proposed novel species was PS06T (= KCTC 43244T = CGMCC 1.17355T).