Role of Bacillus subtilis in Plant Growth Promotion and Disease Suppression: A Review

Because it suppresses diseases and promotes plant growth, the gram-positive, spore-forming rhizobacterium Bacillus subtilis is essential to sustainable agriculture. This review clarifies its mechanisms, which include the production of phytohormones (auxins and gibberellins), nutrient solubilization (phosphorus and potassium), and the release of volatile organic compounds (VOCs) that promote root growth and nutrient uptake. Lipopeptides (surfactin, iturin, and fengycin), bacteriocins, and enzymes like chitinases, which inhibit pathogens like Rhizoctonia solani and Fusarium spp., are the main sources of its biocontrol effectiveness. B. subtilis creates biofilms to guarantee rhizosphere colonization and induces systemic resistance (ISR), which primes plants against biotic and abiotic stresses. Field applications encounter difficulties such as uneven colonization because of soil variability and microbial competition, despite laboratory success. Its stability and effectiveness are improved by formulation innovations like genetic engineering and nano emulsions. Omics methodologies, such as metabolomics and genomics, provide information for maximizing its uses. In order to address global food security and environmental concerns, this review highlights the potential of B. subtilis as a biofertilizer and biopesticide and highlights the necessity of field-scale validation and ecological safety assessments to minimize chemical inputs and encourage sustainable crop production.