Methylobacterium amylolyticum sp. nov. and Methylobacterium ligniniphilum sp. nov., isolated from soil

Two pink-pigmented bacteria, designated strains NEAU-140^T and NEAU-K^T, were isolated from field soil collected from Linyi, Shandong Province, PR China. Both isolates were aerobic, Gram-stain-negative, rod-shaped, and facultatively methylotrophic. 16S rRNA gene sequences analysis showed that these two strains belong to the genus Methylobacterium. Strain NEAU-140^T exhibited high 16S rRNA gene sequence similarities to Methylobacterium radiotolerans NBRC 15690^T (97.43 %) and Methylobacterium phyllostachyos NBRC 105206^T (97.36 %). Strain NEAU-K^T exhibited high 16S rRNA gene sequence similarities to M. phyllostachyos NBRC 105206^T (99.00 %) and Methylobacterium longum DSM 23933^T (98.72 %). A phylogenetic tree based on 16S rRNA gene sequences showed that strain NEAU-140^T formed a clade with Methylobacterium aerolatum (95.94 %), Methylobacterium persicinum (95.66 %) and Methylobacterium komagatae (96.87 %), and strain NEAU-K^T formed a cluster with M. phyllostachyos and M. longum. The predominant fatty acid in both strains was C_18 : 1  ω7c. Both strains contained ubiquinone Q-10 as the only respiratory quinone. The polar lipid profiles of both strains contained diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylcholine. Whole-genome phylogeny showed that strains NEAU-140^T and NEAU-K^T formed a phyletic line with M. aerolatum, M. persicinum, Methylobacterium radiotolerans, Methylobacterium fujisawaense, Methylobacterium oryzae, Methylobacterium tardum, M. longum and M. phyllostachyos. The orthologous average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain NEAU-140^T and its closely related strains were lower than 82.62 and 25.90  %, respectively. The ANI and dDDH values between strain NEAU-K^T and its closely related strains were lower than 86.29 and 31.7 %, respectively. The genomic DNA G+C contents were 71.63 mol% for strain NEAU-140^T and 69.08 mol% for strain NEAU-K^T. On the basis of their phenotypic and phylogenetic distinctiveness and the results of dDDH and ANI hybridization, these two isolates represent two novel species within the genus Methylobacterium, for which the names Methylobacterium amylolyticum sp. nov. (type strain NEAU-140^T=MCCC 1K08801^T=DSM 110568^T) and Methylobacterium ligniniphilum sp. nov. (type strain NEAU-K^T=MCCC 1K08800^T=DSM 110567^T) are proposed.