Microbial inoculants - fostering sustainability in groundnut production

Groundnut (Arachis hypogaea L.) is a vital leguminous oilseed crop, widely cultivated in tropical and subtropical regions due to its high nutritional and economic significance in food, feed, and oil purposes. It is a rich source of protein, oil, vitamins, minerals, and bioactive compounds with anti-inflammatory, anticancer, and anti-aging properties. Globally, groundnut production is approximately 54.2 million tonnes, with India contributing 10.1 million tonnes through rainfed cultivation. However, its productivity is constrained by drought, salinity, soil nutrient deficits, and disease infestations. Conventional farming depends on chemical inputs to enhance yield and productivity but negatively impacts soil health and fertility, reduces microbial diversity, and pollutes agroecosystems, creating an urgent need for sustainable alternatives. Microbe-based bioinoculants comprising nitrogen-fixers, phosphorus solubilizers, potassium solubilizers, sulphur oxidizers, other plant growth-promoting rhizobacteria (PGPR), mycorrhizal fungi, and cyanobacteria offer an alternative approach to enhance the growth and yield of groundnut through various direct and indirect mechanisms, including augmenting nutrient absorption, improving quality parameters, suppressing plant pathogens, stimulating plant defence, and increasing resilience to abiotic stresses. This narrative review examines the diversity, benefits, and growth-promoting mechanisms of rhizospheric, phyllospheric, and endophytic microorganisms associated with groundnut. Additionally, molecular docking of groundnut root exudate metabolites, produced upon microbial inoculation, with stress-responsive proteins highlights the significance of microbial inoculants in mitigating drought and salinity stresses. This review synthesizes recent advances in microbial inoculant applications, highlighting their potential to revolutionize sustainable groundnut cultivation. Therefore, microbial inoculants provide a promising solution ensuring sustainability and assurance of food security amid global difficulties.