Antagonistic potential and plant growth-promoting activities of Bacillus spp. with their tolerance to temperature, salinity, and drought: A review

Abstract

Bacillus spp. are widely recognized for their ecological versatility, antagonistic properties, and plant growth-promoting activities, making them valuable in sustainable agriculture. This review highlights the antagonistic potential of Bacillus isolates against major phytopathogens, including Rhizoctonia solani, Xanthomonas oryzae pv. oryzae and Sclerotium rolfsii. The mechanisms underlying their biocontrol efficacy are discussed, encompassing the production of antimicrobial compounds, nutrient competition and induction of plant systemic resistance. These traits underscore Bacillus spp. as effective bio control agents for managing fungal and bacterial diseases in crops. The review also explores the physiological resilience of Bacillus isolates under abiotic stresses such as extreme temperatures, variable pH conditions, drought and salinity. These stress-tolerance capabilities allow Bacillus spp. to thrive in diverse environments, ensuring their consistent performance as bio-inoculants in field conditions. Moreover, their plant growth-promoting attributes, including nitrogen fixation, phosphate solubilization, production of phytohormones like indole-3-acetic acid and siderophore production, further contribute to enhanced crop productivity and stress mitigation. This review highlights the dual role of Bacillus species in both biocontrol and plant growth promotion, providing valuable insights into their potential for creating sustainable agricultural solutions.