Applied Biotechnology & Bioengineering

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Received: January 01, 1970 | Published: ,

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Editorial

Methylotrophic bacterial community is a very important group of bacteria utilizing reduced carbon compounds. Methylotrophic bacteria are well enough to survive in all types of environmental conditions including acidic/alkaline habitats,^1–3 hyper saline,^4,5 drought,^6–8 low temperature^9–11and high temperature.^6,12,13 The methylotrophic microbes help plant for adaptation under diverse unfavourable environmental conditions. The pink pigmented facultative methylotrophic (PPFMs) bacteria is abundantly reported as plant microbiomes (epiphytes, endophytes, rhizospheric).^11,13,14The methylotrophic microbes could be promote the plant growth and soil health for sustainable agriculture directly by N2-fixation fixation; P, K and Zn solubilization; production of Fe-chelating compounds; production of PGP hormones such gibberellic acids, auxin and cytokinin and ACC deaminase activities^6,11,13,15or by in-directly by production of siderophores, ammonia, HCN, enzymes and secondary metabolites.^16,17 The plant growth promoting methylotrophs as single bioinoculants or with co-inoculated as microbial consortium may be use as bioinoculants/biofertilizers of biocontrol agents for enhanced crops production and soil fertility for sustainable agriculture.^18–21

The different class α, β and γ–proteobacteria of methylotrophic bacteria communities have been reported worldwide. The class α-proteobacteria has been reported as most dominant followed by β–proteobacteria. The novel methylotrophic microbes have been isolated and characterized from different habitats worldwide including Methylocella silvestris BL2T , Methylocella palustris KT, Methyloferula stellata AR4T and Methylocapsa acidiphila B2T from acidic soil;^22–25 Methylobacterium tarhaniae N4211T from arid soil;²⁶ Methylobacterium iners 5317S-33T and Methylobacterium aerolatum 5413S-11T from air sample;²⁷ Methylobacterium adhaesivum AR27T and Methylobacterium isbiliense AR24T from drinking water;^28,29 Methylobacterium brachiatum B0021T, Methylobacterium gregans 002-074T, Methylobacterium komagatae 002-079T, Methylobacterium persicinum 002-165T and Methylobacterium tardum RB677T from freshwater sample;³⁰ Methylobacterium organophilum XX, Methylotenera versatilis 301T and Methylotenera mobilis JLW8T from lakes;^31–33 Methylobacterium brachythecii 99bT, Methylobacterium cerastii C44, Methylobacterium gnaphalii 23eT, Methylobacterium gossipiicola Gh-105T, Methylobacterium haplocladii 87eT, Methylobacterium oxalidis 35aT, Methylobacterium phyllosphaerae B27T, Methylobacterium phyllostachyos BL47T, Methylobacterium platani PMB02T, Methylobacterium pseudosasicola BL36T, Methylobacterium thuringiense C34T, Methylobacterium trifolii TA73T, from leaf surface of diverse plants;^34–42 Methylobacterium aminovorans TH-1, Methylobacterium goesingense iEII3, Methylobacterium soli YIM 48816T, Methylobacterium suomiense, F20T, Methylobacterium thiocyanatum, Methylobacterium variabile GR3T, Methylopila capsulata IM1T, and Methylopila helvetica VKMB-189 from soil samples^43–50

To understand the mechanisms of plant growth promotion and genes involved in plant growth promotion there are many reports on whole genome sequences of methylotrophic bacteria are available at NCBI GenBank database (https://www.ncbi.nlm.nih.gov) Methylobacterium populi BJ001, Methylobacterium extorquens CM4, Methylobacterium nodulans ORS 2060, Methylobacterium aquaticum MA-22A, Methylobacterium radiotolerans JCM 2831, Methyloferula stellata AR4, Methylotenera mobilis JLW8, Methylotenera versatilis 301, Methylobacterium sp. AMS5, Methylotenera versatilis 301 Methylotenera mobilis JLW8, Methylovorus glucosetrophus SIP3-4, Methylovorus glucosetrophus SIP3-4, Methylobacterium mesophilicum SR1.6/6, and Methylobacterium indicum SE2.11

Plant-associated methylotrophs produce PGP phytohormones such as auxins, gibberellins and cytokinin by Methylobacterium extorquens IIWP-43, M. extorquens MP1, M. mesophilicum B-2143, M. mesophilicum HHS1-36, M. mesophilicum IIWP-45, M. mesophilicum NIAW1-41, M. phyllosphaerae HHS2-67, M. radiotolerans HHS1-45, M. radiotolerans IHD-35 and M. zatmanii MS4. Many methylotrophs has been reported to fix N2 e.g. Methylobacterium mesophilicum B-2143, M. nodulans 2060T, and Methylobacterium sp. THD-3511,^51–56. A vast number methylotrophs with P-solubilizing ability have been reported Methylobacillus arboreus Iva, M. extorquens G10, M. extorquens IIWP-43, M. lusitanum MSF 32, M. mesophilicum IIWP-45, M. mesophilicum NIAW1-41, M. radiotolerans IHD-35, Methylopila musalis MUSA and Methylovorus menthalis MM.^2,6,13,57,58

Conclusion

The methylotrophic microbes from diverse sources have potential applications in agriculture, industry and allied sectors. The methylotrophic bacteria could be used for plant growth and soil health for sustainable agriculture when inoculated as single or as consortium under the natural as well as abiotic stress conditions.

Acknowledgements

The authors are grateful to Prof. Harcharan Singh Dhaliwal, Vice Chancellor, Eternal University, Baru Sahib, Himachal Pradesh, India for providing infra-structural facilities and constant encouragement.