Microbial biofertilizers: A sustainable agricultural approach to augment crop resilience against biotic and abiotic stresses

Increasing plant growth and yield with the aid of plant growth-promoting bacteria is a widely accepted, eco-friendly and economic approach in modern agriculture. Their use as an alternative to widely used harmful chemical fertilizers and pesticides can improve overall soil health and fertility, thereby enhancing crop yield. The positive modulation of genes related to growth and development, fruit formation, stress tolerance and phytohormone production helps plants significantly during maturation. Furthermore, the enhanced production and expression of defence-related hormones aid in survival under various stress conditions, such as drought, pH fluctuations, salinity and water stress. In addition, the application of growth-promoting bacteria, mainly from species such as Azospirillum, Bacillus, Klebsiella, Enterobacter, Pseudomonas, Azotobacter, Burkholderia, Rhizobium, Alcaligenes, Arthrobacter and Serratia supports plant growth and development by improving soil porosity, pH and salinity conditions. This review briefly outlines the role of the plant growth-promoting bacteria as microbial biofertilizers that enhance crop resilience under both biotic and abiotic stress conditions. By highlighting recent advances in understanding the mechanisms of microbe-plant interactions under these stresses, it also provides unique insights into how microbial biofertilizers can be employed for sustainable agriculture. This has direct relevance for policymakers and farmers by reducing dependence on chemical fertilizers, which have various negative impacts, thereby promoting long-term environmental sustainability and improved agricultural practices.