Methylobacterium crusticola sp. nov., isolated from biological soil crusts

Abstract

A pink-pigmented, Gram-negative, rod-shaped, obligate aerobic bacterial strain, MIMD6^T, was isolated from biological soil crusts in PR China. Cells grew at 20-37 °C (optimum, 30 °C), at pH 6-8 (optimum, pH 7) and with 0-1 % (w/v) NaCl (optimum, 0 %). Strain MIMD6^T could use methanol or formate as a sole carbon source to grow, and carried methanol dehydrogenase genes mxaF and xoxF, supporting its methylotrophic metabolism. The respiratory quinone was ubiquinone Q-10, the major fatty acids were C_{18 : 1}ω7c (87.3 %), and the major polar lipids were diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unknown aminolipid and one unidentified glycolipid. The results of phylogenetic analyses based on the sequences of the 16S rRNA gene, seven housekeeping genes (dnaK, recA, rimO, rpIK, rpmG, rpsR and rpoB) and methanol dehydrogenase genes indicated that strain MIMD6^T formed a phylogenetic linage with members of the genus Methylobacterium. Strain MIMD6^T was most closely related to Methylobacterium isbiliense DSM 17168^T and Methylobacterium nodulans LMG 21967^T with 16S rRNA gene sequence similarities of 95.7 and 95.2 %, respectively. The genomic DNA G+C content calculated via draft genome sequencing was 73.0 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain MIMD6^T and the type strains of other Methylobacterium species were 70.7-82.0 and 24.6-30.0 %, respectively. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, strain MIMD6^T represents a novel species of the genus Methylobacterium, for which the name Methylobacterium crusticola sp. nov. is proposed. The type strain is MIMD6^T (=KCTC 52305^T=MCCC 1K01311^T).

Keywords: Alphaproteobacteria; Methylobacteriaceae; Methylobacterium; Rhizobiales; biological soil crusts.