MICROBIOME-DRIVEN PLANT DEFENCE AGAINST ROOT-KNOT NEMATODES: INTEGRATIVE MECHANISMS AND APPLICATIONS

Abstract

Root knot nematodes (RKNs) (Meloidogyne spp.) are among the most destructive plant parasitic nematodes (PPNs), causing severe yield losses across global agriculture. They establish permanent feeding sites known as giant cells within the vascular tissues of host roots disrupting nutrient transport and predisposing plants to secondary infections. Conventional nematicides and cultural practices are increasingly limited by environmental concerns, regulatory restrictions, broad host ranges, and the emergence of highly virulent species such as M. enterolobii. The plant microbiome that comprising rhizosphere, rhizoplane, endophytic, and phyllosphere communities functions as an extended defence system that enhances plant resilience to nematode attack. Beneficial microorganisms including Bacillus, Pseudomonas, Paenibacillus, Streptomyces, Trichoderma, Pochonia, Purpureocillium, and arbuscular mycorrhizal fungi suppress RKNs through direct antagonism (nematicidal metabolites, hydrolytic enzymes, parasitism), modulation of root architecture and exudation, and activation of induced systemic resistance (ISR), systemic acquired resistance (SAR), and mycorrhiza induced resistance (MIR). Microbial metabolitessuch as lipopeptides, phenazines, peptaibols, VOCs (e.g., dimethyl disulfide, 1 octen 3 ol), and fatty acids (lauric, palmitic) alter nematode behaviour, inhibit egg hatching, and prime plant immune pathways involving JA, SA, ET, ROS signaling, and antioxidant enzymes. Advances in metagenomics, meta-transcriptomics, metabolomics, and effector biology have revealed the molecular basis of plant–microbe–nematode interactions and identified key microbial taxa associated with disease suppressive soils. Microbiome engineering, synthetic microbial communities (SynComs), host mediated microbiome selection, and soil health management offer promising avenues for sustainable nematode control. This review integrates ecological, physiological, and molecular insights into microbiome driven defence against RKNs, highlights key microbial players and their synergistic interactions, and outlines future directions for precision microbiome engineering, climate resilient biodefence, and field level translation. Harnessing microbiome enabled resilience provides a scalable, eco friendly alternative to chemical nematicides and represents a transformative strategy for sustainable nematode management in modern agriculture.