Bacterial Secondary Metabolites (B-SMs): Empowering Agriculture Against Fungal Disease Challenges

Bacterial secondary metabolites (B-SMs) are bioactive, low molecular weight compounds synthesized during the bacteria idio phase within their metabolic cycle. These specialized metabolites are dispensable for bacterial growth but are pivotal in eliciting secondary response mechanisms such as resistance, survival, and defense. Rhizobacteria, encompassing genera such as Bacillus, Pseudomonas, Micrococcus, Streptomyces, members of Actinomycetes such as Nocardia spp., are prolific producers of secondary metabolites characterized by their diverse physiochemical and biotic properties. Among these metabolites are pigments, toxins, antibiotics, and antitumor agents. Notably, rhizobacterial B-SMs exhibit biocontrol activities, including potent antifungal, antiviral, and antibacterial effects. This Chapter reviews some secondary metabolites synthesized by various rhizobacterial species, particularly highlighting their antifungal properties, and offers insights into characterization methodologies and advanced analytical techniques.