Methylobacterium

Abstract

Me.thy.lo.bac.te'ri.um. N.L. pref. methylo , pertaining to the methyl radical; Gr. n. bacterion , a small rod; N.L. neut. n. Methylobacterium , a methyl radical utilizing bacterium. Proteobacteria / Alphaproteobacteria / Rhizobiales / Methylobacteriaceae / Methylobacterium The genus Methylobacterium accommodates pink‐pigmented, facultatively methylotrophic (PPFM) bacteria that assimilate single carbon substrates via the serine cycle. A recent revision of the taxonomy has grouped all Methylobacterium sensu lato species in three distinct clades: Methylobacterium sensu stricto (Clade A), Methylorubrum (Clade B), and the third clade (Clade C), which contains some nonmethylotrophic species and currently remains within Methylobacterium sensu lato . Most species form pink to orange‐red colonies on methanol salt media; colonies are circular, convex with entire margins. Cells are non‐spore‐forming rods that occur singly, in pairs, or occasionally in rosettes and may be branched or pleomorphic. Gram‐negative with a Gram‐negative cell wall type but may stain Gram‐variable. Cells of most species are motile by means of one or more polar, subpolar, or lateral flagella. Respiration is strictly aerobic. They are mesophilic and chemoorganotrophic. Strains belonging to Methylobacterium sensu stricto are facultatively methylotrophic, being able to grow with formaldehyde, formate, and methanol as sole carbon sources; most strains are unable to grow on methylamine. Clade C within Methylobacterium sensu lato contains some members that are unable to utilize methanol or formaldehyde. Some strains have shown evidence of weakly phototrophic growth. Can grow on a variety of multicarbon compounds, in particular organic acids, but most strains are unable to utilize disaccharides. The major cellular fatty acid is C 18:1 ω7 c and/or C 18:1 ω6 c . DNA G + C content is 66.0–73.0 (genome). Methylobacterium species are widely distributed in nature, being found in soil, water, and associated with plants, most commonly in the phyllosphere. Methylobacterium organophilum is the type species of this genus. DNA G + C content (mol%) : 66.0–73.0 (genome). Type species : Methylobacterium organophilum Patt et al. 1976 AL .