Gamma radiation-induced enhancement of biocontrol agents for plant disease management

Abstract

Gamma radiation-induced mutations in microorganisms can enhance their properties for the biological control of plant diseases. Mutant strains of Bacillus subtilis were found to have improved antifungal properties against Aspergillus flavus and increased production of biosurfactants and biofilms. Furthermore, combining gamma radiation with antagonists was more effective in controlling Penicillium expansum postharvest than either treatment alone. A major focus of this research was on Trichoderma species, which have shown an enhanced ability to control plant diseases through increased production of antifungal metabolites such as hydrolytic enzymes, antibiotics, and total phenols. The mechanism by which gamma radiation alters the genotype of microorganisms is the destruction of double-stranded and single-stranded DNA, resulting in changes in the genome or nucleic acid molecule, altering the antagonistic properties of microorganisms. Sensitivity to radiation is determined by the size of an organism's chromosomes, and the effect on microorganisms is primarily based on DNA or RNA disruption. Molecular analysis of gamma radiation mutants has been used to understand changes in genome composition, including downregulated genes related to secondary metabolism, cytochrome P450 s, carbohydrate-active enzymes, peptidases, and hydrophobins. Gamma radiation thus offers a promising method to induce beneficial genetic changes in microorganisms, enhancing their efficacy in the biological control of plant diseases.