Pink Pigmented Facultative Methylotrophs (PPFMs): Potential Bioinoculants for Sustainable Crop Production

Abstract

Bacteria belonging to the genus Methylobacterium, popularly known as pink pigmented facultative methylotrophic (PPFM) bacteria, are well known for their distinct ability to use single-carbon compounds like methanol, formate and formaldehyde, and also a variety of multi-carbon substrates lacking carbon-carbon bonds. These bacterial groups are ubiquitously distributed, especially in phyllosphere and rhizosphere, and their occurrence have been reported in more than 100 species of plants so far. PPFMs have profound influence on soil fertility, crop growth and yield. The ability for phosphate acquisition, nitrogen fixation, iron chelation and phytohormone production indicate the possibility of developing them as promising biofertilizer candidates. In addition, many of them possess biocontrol activity against several phytopathogens. PPFMs induce several physiological changes in plants, making the plants more resistant to biotic and abiotic stress. They can therefore be promising alternatives to conventional chemical inputs in sustainable agricultural systems.