ABSTRACT
Microbes play an important role in affecting plant health. The nonpathogenic microbes such as Bacillus spp., Actinobacteria, Pseudomonads, Rhizobium and Trichoderma offer a sustainable, ecofriendly and economical solution for the management of various crop diseases compared with chemical-based management practices. Several mechanisms including production of cell wall hydrolases and bioactive secondary metabolites targeting the plant pathogens are considered to play important roles in the biocontrol activity of these microbes. In particular, the production of low-molecular weight peptides having ability to target the pathogen cell wall or membrane offer attractive choice for future plant disease management. These peptides are broadly categorized into ribosomal and nonribosomal peptides. The genomes of beneficial microbes harbor wide gene clusters of ribosomal-synthesized peptides in canonical fashion, whereas peptides of nonribosomal are modular in their organization. The posttranslational modified peptides of ribosomal origin include lanthipeptides, tail-cyclized peptides, sactipeptides, unmodified bacteriocins, and 242other large antimicrobial proteins. On the other side, the antimicrobial peptides (AMPs) synthesized by nonribosomal peptide synthetase enzyme complexes represent a diverse class of peptaibols. This chapter highlights the nature, mechanism, and the potential of these AMPs from beneficial microbes for the biological management of plant diseases.
