Review of the genus Methylobacterium and closely related organisms: a proposal that some Methylobacterium species be reclassified into a new genus, Methylorubrum gen. nov

• Published in: International journal of systematic and evolutionary microbiology Vol. 68; no. 9; pp. 2727 - 2748
• Main Authors: Green, Peter N, Ardley, Julie K
• Format: Journal Article
• Language: English
• Published: England 01-09-2018
• Subjects: Methylorubrum; mxaF; methanol; methylamine; MLSA; Methylobacterium; xoxF
• ISSN: 1466-5026; 1466-5034
• DOI: 10.1099/ijsem.0.002856

The genus Methylobacterium, when first proposed by Patt et al. in 1976, was a monospecific genus created to accommodate a single pink pigmented facultatively methylotrophic bacterium. The genus now has over 50 validly published species, however, the percentage 16S rRNA sequence divergence within Methylobacterium questions whether or not they can still be accommodated within one genus. Additionally, several strains are described as belonging to Methylobacterium, but nodulate legumes and in some cases are unable to utilize methanol as a sole carbon source. This study reviews and discusses the current taxonomic status of Methylobacterium. Based on 16S rRNA gene, multi-locus sequence analysis, genomic and phenotypic data, the 52 Methylobacterium species can no longer be retained in one genus. Consequently, a new genus, Methylorubrum gen. nov., is proposed to accommodate 11 species previously held in Methylobacterium. The reclassified species names are proposed as: Methylorubrum aminovorans comb. nov. (type strain TH-15
=NCIMB 13343
=DSM 8832
), Methylorubrum extorquens comb. nov. (type strain NCIMB 9399
=DSM 1337
), Methylorubrum podarium comb. nov. (type strain FM4
=NCIMB 14856
=DSM 15083
), Methylorubrum populi comb. nov. (type strain BJ001
=NCIMB 13946
=ATCC BAA-705
), Methylorubrum pseudosasae comb. nov. (type strain BL44
=ICMP 17622
=NBRC 105205
), Methylorubrum rhodesianum comb. nov. (type strain NCIMB 12249
=DSM 5687
), Methylorubrum rhodinum comb. nov. (type strain NCIMB 9421
=DSM 2163
), Methylorubrum salsuginis comb. nov. (type strain MR
=NCIMB 14847
=NCCB 100140
), Methylorubrum suomiense comb. nov. (type strain F20
=NCIMB 13778
=DSM 14458
), Methylorubrum thiocyanatum comb. nov. (type strain ALL/SCN-P
=NCIMB 13651
=DSM 11490
) and Methylorubrum zatmanii comb. nov. (type strain NCIMB 12243
=DSM 5688
). The taxonomic position of several remaining species is also discussed.