Insights into the application and functional mechanisms of biocontrol against fungal pathogens in rice

Abstract

More than 50% of the world's population is reliant on rice (Oryza sativa L.) as their main dietary source, but harmful fungal diseases are a constant threat to its production. Each year, significant yield losses occur due to pathogens like Rhizoctonia solani (sheath blight), Magnaporthe oryzae (rice blast) and Ustilaginoidea virens (false smut). The frequent use of chemical fungicides used to treat these diseases have led to the development of tolerance pathogen stress and serious environmental issues. A viable and long-term alternative is biological control, which makes use of more beneficial microorganisms called biocontrol agents (BCAs). This review summarizes recent findings on the use and actual mechanisms of BCAs against the primary rice fungal pathogens. We analyze the variety of microbial antagonists, which comprise the fungal and bacterial genera Trichoderma and Bacillus, Pseudomonas, and Streptomyces and other endophytic fungi. These BCAs have a variety of functional mechanisms, include competition for nutrients and space, direct hostility through mycoparasitism, and antibiosis, as well as indirect mechanisms such as the induction of systemic resistance (ISR) in the host plant and plant growth promotion (PGP).We discuss a variety of methods of application, like as foliar sprays, soil inoculation, and seed dressing, and focus on the significance of developing stable and efficient formulations. In order to improve the efficacy and reliability of biocontrol in rice agroecosystems, we deal with the issues preventing the broad use of BCAs, such as uneven field performance and regulatory barriers, and we suggest future research possibilities, such as the development of synthetic microbial consortia and the application of multi-omics technologies.