Methylobacterium oryzisoli sp. nov., a novel methylotrophic methanol-utilizing bacterium isolated from the paddy soil.

Abstract

Four pink-pigmented bacteria, designated as strains sgz302003^T, sgz302004, sgz302005 and sgz302006, were isolated from a paddy soil enrichment. The cells were aerobic, Gram-stain-negative, motile and short rods. The ranges and optima of the temperature, NaCl concentration and pH for growth were 25-37 °C (optimum, 30 °C), 0-2% (w/v) (optimum, 0-0.5%) and pH 5.0-10.0 (optimum, pH 6.5), respectively. Major fatty acids were summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c). Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that the four strains were affiliated with the genus Methylobacterium and were most closely related to Methylobacterium isbiliense AR24^T (99.2% sequence similarity), Methylobacterium nodulans ORS 206^T (97.7%) and Methylobacterium currus PR1016A^T (97.4%). The methanol dehydrogenase mxaF gene was absent, but xoxF was present. Phylogenomic tree supported that these four strains formed a distinct clade within Methylobacterium. Q-10 was detected as the only respiratory quinone in the studied strains. The genomic DNA G+C content was 70.7-70.8 %. The orthologous average nucleotide identity and in silico digital DNA-DNA hybridization values between the four strains and M. isbiliense AR24^T were 91.8-91.9% and 53.0-53.3%, respectively, while those with M. nodulans ORS 206^T were 86.3-86.5% and 25.5%. Phylogenomic, physiological and chemotaxonomic analyses indicate that the four strains represent a novel species within the genus Methylobacterium, for which the name Methylobacterium oryzisoli sp. nov. is proposed, with strain sgz302003^T (= MCCC 1K09384^T=KCTC 8693^T) as the type strain.