Exploiting the biocontrol potential of plant growth promoting Bacillus species to control plant pathogenic fungi

According to recent investigations, the harmful effects of plant pathogenic fungi are increasing, causing significant economic losses to crops worldwide. Chemical fungicides utilized since 1940s have negative consequences for the environment and living organisms, and fungal resistance is developed in some cases. One of the most effective alternatives is biological control, which utilises plant-associated bacteria or biological compounds. Plant growth-promoting rhizobacteria, such as Bacillus species, can enhance plant growth and health while also protecting them against fungal diseases, making them a potential alternative to chemical fertilizers and pesticides. Bacillus species can form spores that survive in harsh environments for long periods. However, the biocontrol abilities of Bacillus species have not been fully realized, and extensive research in this field is required to understand and transfer lab findings to real-world applications. This review explores the role of Bacillus species as a plant growth-promoting agent, its mechanisms of biocontrol against fungal phytopathogens, and how it can improve crop productivity. Additionally, this review highlights the genomic and molecular insights into the antifungal machinery of Bacillus species, while also providing detailed guidance on its application process to exert induced systemic resistance in agricultural practices. It also identifies knowledge gaps and areas for further research to improve Bacillus-based biocontrol agents that can exert induced systemic resistance.