Methylobacterium is a genus of bacteria, also designated as Pink-Pigmented Facultative Methylotrophs (PPFMs). Methylobacterium is commonly found in soil, water, and particularly in association with the phyllosphere, the aerial part of plants.[2][3]Methylobacterium is characterized by its ability to metabolize one-carbon compounds like methanol released by plant leaves.[4]Methylobacterium plays key roles in nutrient cycling and plant-microbe interactions, often promoting plant growth and resilience through hormone production and stress mitigation.[5][6]Methylobacterium is a model in biotechnology, already used commercially for protein production, bioremediation, and as a biostimulant in agriculture.[7][8]
Methylobacterium has also been identified as a contaminant of DNA extraction kit reagents, which may lead to its erroneous appearance in microbiota or metagenomic datasets.[9] In March 2021, a new species, named Methylobacterium ajmalii,[10] associated with three new strains, designated IF7SW-B2T, IIF1SW-B5, and IIF4SW-B5, were reported to have been discovered, for the first time, on the International Space Station.[11][12]
Consensus phylogeny of Methylobacterium species built from 213 Methylobacteriaceaegenomes (adapted from Leducq et al. 2022 [13])
Debate on Methylobacterium taxonomy
In 2018, 11 Methylobacterium species, including Methylobacterium extorquens, were transfered to Methylorubrum.[14] This emendation mostly relied on the 16S rRNA genephylogeny. In 2021 and 2022, two studies based on phylogenomic and phenotypic data independently pointed the lack of support for Methylorubrum as a distinct genus, calling for its abandonment and the reinstatement of the former Methylobacterium taxonomy.[15][16] In 2025, despite controversy, and its emendation back to the original Methylobacterium taxonomy,[16]Methylorubrum was still a valid genus name in some databases like NCBI and in the List of Prokaryotic names with Standing in Nomenclature.[17]
Natural genetic transformation
Natural genetic transformation in bacteria is a process involving transfer of DNA from one cell to another through the intervening medium, and the integration of the donor sequence into the recipient genome by homologous recombination. Methylobacterium organophilum cells are able to undergo genetic transformation and become competent for DNA uptake near the end of the exponential growth phase.[18]
Species
Methylobacterium comprises the following species[19] (excluding species reclassified in Methylorubrum[14]):
^Govindaraju, Alekhya; Good, Nathan M; Zytnick, Alexa M; Martinez-Gomez, Norma Cecilia (1 June 2022). "Employing methylotrophs for a green economy: one-carbon to fuel them all and through metabolism redesign them". Current Opinion in Microbiology. 67: 102145. doi:10.1016/j.mib.2022.102145.
^Rogers, Adam (April 5, 2021). "Sneaky New Bacteria on the ISS Could Build a Future on Mars". Wired. One species, found on a HEPA filter in the station's life-support system, was a garden-variety (literally!) Methylobacterium rhodesianum. But three samples—from a surface near the materials research rack, a wall near the "cupola" of windows, and the astronauts' dining table—were something new.
