Molecular Biology of Biocontrol Activity Against Crop Diseases

Abstract

As an ecofriendly strategy of crop disease management, use of biocontrol agents (BCAs) for protecting crops against diseases has attracted the attention of researchers, industries and consumers of agricultural and horticultural produce. Although several microbes have been shown to have the potential for use as BCAs, the satisfactory performance under field conditions has been proved only for a few of them. Molecular techniques have been applied to establish the identity and genetic diversity of microorganisms with potential biocontrol activity and to gather information on the genes required for and molecular determinants of the biocontrol activity of different BCAs. The studies on the molecular bases of the three-way interaction among the plant, BCA and pathogen have opened up the possibility of having a better understanding of how the BCAs search for the pathogen, talk to the host plant and survive in the environment. Use of biocontrol agents (BCAs) is considered as a desirable crop disease management strategy alternative to chemical application due to ill effects of chemicals to the environment, consumers of agricultural produce and non-target organisms. Molecular techniques have accelerated the pace of research endeavors to gather information on various aspects of BCAs and their interaction with pathogens and plants. The BCAs can interact with the microbial pathogens by producing different toxic metabolites such as enzymes and antimicrobial compounds. They also have the ability to indirectly interact with pathogens by inducing resistance in plants to diseases caused by them. The foremost step in the study of molecular biology of the BCAs is establishing the identity of the BCAs with certainty at genus, species, subspecies or strain level. This will be essential for the reproducibility and credibility of the tests performed at various centers and for patenting and development of BCA-based products for large scale application.