Multifunctional Roles of Bacillus spp. in Sustainable Agriculture: Advances in Biocontrol, Omics, and Ecological Applications

The intensifying demand for sustainable agriculture necessitates eco-friendly alternatives to synthetic agrochemicals. Bacillus spp., a versatile group of plant-associated rhizobacteria, have emerged as potent biocontrol agents with multifaceted roles in promoting crop health and resilience. This review synthesizes recent advances in the ecological and functional understanding of Bacillus spp., emphasizing their mechanisms of action, including antibiosis, siderophore production, biofilm formation, induction of systemic resistance, and secretion of lytic enzymes. The capacity of Bacillus to modulate phytohormone levels, improve nutrient acquisition, and mitigate abiotic stresses underpins their role as effective plant growth-promoting rhizobacteria (PGPR). Moreover, their ability to combat a broad spectrum of phytopathogens, fungal, bacterial, viral, nematodal, and insect pests, highlights their biocontrol potential in diverse agroecosystems. Advances in omics technologies have unraveled critical genes and regulatory pathways governing these beneficial traits, enabling targeted genetic engineering for enhanced efficacy and environmental adaptability. Despite their widespread applicability, gaps remain in formulation stability, field performance consistency, and regulatory harmonization. This review underscores the need for integrative research combining microbial ecology, genomics, and precision agriculture to optimize Bacillus-based biocontrol strategies for climate-resilient and sustainable crop production.