Mechanism of Antagonistic Bioagents in Controlling Root-Knot Nematodes (Meloidogyne sp.): A Review

Root-knot nematodes are among the most significant pathogenic organisms due to their global distribution, capacity for destruction, and economic importance. Antagonistic bioagents are more effective alternative to synthetic pesticides in the suppression of root-knot nematodes. Bioagents reduce the use of synthetic chemicals, which are hazardous to both humans and the environment. Despite this, some bioagents, such as fungi and bacteria have unknown mechanisms. This review discusses the nematophagous bacteria and fungi that have been discovered so far, including Pochonia, Trichoderma sp., Pseudomonas sp., and Bacillus sp., with an overview of the current advances in research regarding their molecular and biochemical control mechanisms. Biological control agents (BCAs), as valuable ecological enemies of nematode infestations, use a range of mechanisms, such as parasitism, nutrient competition, toxin production, induce systemic resistance to antibiotics, enzymes, and enhance plant health. They suppress nematodes directly, improve plant growth, and facilitate the colonization and activities of antagonistic microbes in the rhizosphere. Understanding the molecular basis of BCAs suppression mechanisms provides the basis for their future incorporation into phytopathogen or plant disease control management. This study reviews the current threat posed by the root-knot nematode, biological control, antagonistic bioagents, and their mechanisms, and the future perspectives in modern agricultural sustainability to provide basis for the broad control of root-knot nematodes.