Methylobacillus arboreus sp. nov., and Methylobacillus gramineus sp. nov., novel non-pigmented obligately methylotrophic bacteria associated with plants

Abstract

Two newly isolated obligate methanol-utilizing bacteria (strains Iva T and Lap T) with the ribulose monophosphate pathway of C 1 assimilation are described. The isolates are strictly aerobic, Gram negative, asporogenous, motile rods multiplying by binary fission, mesophilic and neutrophilic, synthesize indole-3-acetate. The prevailing cellular fatty acids are straight-chain saturated C 16:0 and unsaturated C 16:1 acids. The major ubiquinone is Q-8. The predominant phospholipids are phosphatidylethanolamine, phosphatidylglycerol and cardiolipin. Ammonia is assimilated by glutamate dehydrogenase. The DNA G+C contents of strains Iva T and Lap T are 54.0 and 50.5 mol% ( T m), respectively. Based on 16S rRNA gene sequence analysis and DNA–DNA relatedness (38–45%) with type strains of the genus Methylobacillus, the novel isolates are classified as the new species of this genus and named Methylobacillus arboreus Iva T (VKM B-2590 T, CCUG 59684 T, DSM 23628 T) and Methylobacillus gramineus Lap T (VKM B-2591 T, CCUG 59687 T, DSM 23629 T). The GenBank accession numbers for the 16S rRNA gene and mxaF gene sequences of the strains Iva T and Lap T are GU937479, GU937478 and HM030736, HM030735, respectively.