Plant growth-promoting rhizobacteria and millets: A sustainable solution for food security

Millets are grain crops of high agronomical importance in dry and semi-arid areas of the world. They are nutrient-rich minor cereals, resistant to pests, diseases, salt, heat, and drought stress. During the large-scale millet cultivation, farmers continue to deal with issues including poor soil fertility, scarce water supplies, climate change, and low production. Plant growth-promoting rhizobacteria (PGPR) are very useful microbes; they colonize plant roots and promote plant growth and development. Furthermore, they improve the plant yield through a variety of activities, such as secretion of plant hormones and secondary metabolites, solubilization of nutrients, nitrogen fixation, and providing biotic and abiotic stress tolerance. In addition, PGPR increases the fresh weight, dry weight, root length, shoot length, chlorophyll content, proline content, and antioxidant activities, and decreases the malondialdehyde content as well as electrolyte leakage of millet seedlings. PGPR contributes to soil fertility by mineralizing organic matter, removing pollutants and pesticides, phytoextracting and detoxifying heavy metals, and mineralizing organic matter.