ABSTRACT
Bacillus is a class of gram-positive bacteria that is capable of producing spores and withstanding harsh environmental conditions. It is capable of adopting various phenotypic and genotypic forms depending on the environmental conditions to which they are exposed. They produce metabolites and suitably modify themselves using unique strategies such as sporulation and biofilm formation to survive in diverse habitats. Bacillus is an endophytic microbe known to reside inside plants and influence the expression of certain vital genes of plants. They also trigger the balance of the microbial community that dwells in the rhizosphere of the root around the plants. The planktonic and polymeric biofilm community of Bacillus is used as both a biocontrol agent and plant growth-promoting bacteria. It is capable of producing antimicrobial agents with a wide range of action spectrum, hydrolyzing enzymes, secondary metabolites like hydrogen cyanide and siderophores for controlling plant infections. It also produces certain metabolites like indole acetic acid, gibberellic acid and other metabolites by colonizing the rhizosphere of the root which helps in the growth and proliferation of plants. Bacillus species also help the plant in withstanding various environmental stress conditions like drought and salt conditions. This chapter describes the roles and mechanisms adopted by Bacillus in the production of biopolymers and metabolites capable of plant growth promotion and crop protection emphasizing the antifungal activity and the mechanisms underlying the property.
