Methylorubrum extorquens is a Gram-negative bacterium. Methylorubrum species often appear pink, and are classified as pink-pigmented facultative methylotrophs, or PPFMs.^[4] The wild type has been known to use both methane and multiple carbon compounds as energy sources.^[4] Specifically, M. extorquens has been observed to use primarily methanol and C₁ compounds as substrates in their energy cycles.^[5] It has been also observed that use lanthanides as a cofactor to increase its methanol dehydrogenase activity^[6][7]

Genetic structure

After isolation from soil, M. extorquens was found to have a single chromosome measuring 5.71-Mb.^[8] The bacterium itself contains 70 genes over eight regions of the chromosome that are used for its metabolism of methanol.^[9] Within a section of the chromosome, of M. extorquens AM1 are two xoxF genes that enable it to grow in methanol.^[9]

M. extorquens AM1 genome encodes a 47.5 kb gene of unknown function. This gene encodes an over 15,000 residue-long polypeptide along with three unique compounds that are not expressed.^[10] The microbe uses the mxa gene^[11] as a way to dehydrogenate methanol and use it as an energy source.^[10]

Chemical use

Methylorubrum extorquens uses primarily C₁ and C₂ compounds to grow.^[9] Utilizing compounds with few carbon-carbon bonds allows the bacterium to successfully grow in environments with methanol, such as on the surface of leaves whose stomata emit methanol.^[12] The ability to use methanol as both a carbon and energy source was show to be advantageous when colonizing Medicago truncatula.^[13]

H₄MPT-dependent formaldehyde oxidation was first isolated in M. extroquens AM1 and has been used to define if an organism is utilizing methylotrophic metabolism.^[10]

Relationships with other organisms

Many bacteria within the family Methylobacteriaceae live in different biotic environments such as soils, dust, and plant leaves.^[14] Some of these bacteria have been found in symbiotic relationships with the plants they inhabit in which they provide fixed nitrogen or produce vitamin B₁₂.^[14] M. extorquens also produces PhyR which plants use to regulate stress response, allowing the plant to survive in different conditions.^[15] In addition to PhyR, the bacterium can produce a hormone related to overall plant and root growth.^[9]

M. extorquens has been found to have a mutualistic relationship with strawberries.^[16] Ultimately, M. extorquens is used to oxidize 1,2-propanediol to lactaldehyde, which is later used in chemical reactions.^[17] If introduced to blooming plants, furaneol production increases, changing the way the strawberry tastes.^[16]

See also

• Methylacidiphilum fumariolicum
• Methylobacterium radiotolerans

References

External links

• Methylorubrum J.P. Euzéby: List of Prokaryotic names with Standing in Nomenclature
• Methylobacterium extorquens NCBI
• Type strain of Methylobacterium extorquens at BacDive - the Bacterial Diversity Metadatabase