Rhizobium deserti sp. Nov Isolated from Biological Soil Crusts Collected at Mu Us Sandy Land, China

Abstract

A novel gram-negative, aerobic, non-spore-forming, rod-shaped, and non-nitrogen-fixing bacterium, named SPY-1^T, was isolated from biological soil crusts collected at Mu Us Sandy Land, China. Based on 16S rRNA sequence similarity, strain SPY-1^T was most closely related to Neorhizobium alkalisoli CCTCC AB 2014138^T (98.7%), Neorhizobium huautlense CGMCC 1.2538^T (98.6%), Neorhizobium galegae DSM 11542^T (98.4%), Rhizobium wenxiniae 166^T (97.9%), and Rhizobium smilacinae CCTCC AB 2013016^T (97.5%). Phylogenetic analysis based on 16S rRNA sequencing and multilocus sequence analysis of partial sequences of atpD-glnII-glnA-recA-ropD-thrC housekeeping genes both indicated that strain SPY-1^T was a member of the genus Rhizobium. The draft genome of strain SPY-1^T was 4.75 Mb in size, and the G + C content was 60.0%. The average nucleotide identity (ANI) values to N. alkalisoli CCTCC AB 2014138^T and R. smilacinae CCTCC AB 2013016^T were both 84.0%. The digital DNA-DNA hybridization (dDDH) values to N. alkalisoli CCTCC AB 2014138^T and R. smilacinae CCTCC AB 2013016^T were 20.9% and 20.2%, respectively. The major cellular fatty acids were summed feature 8 (C_18:1ω7c and/or C_18:1ω6c) and C_16:0. Based on the data from chemotaxonomic, phylogenetic, and phenotypic evidence, strain SPY-1^T represents a novel species in the genus Rhizobium, for which the name Rhizobium deserti sp. nov. is proposed. The type strain is SPY-1^T (= ACCC 61627^T = JCM 33732^T).

Keywords: Biological soil crusts; Mu Us Sandy Land; Rhizobium; Rhizobium deserti; Soil.