Molecular Interactions Between Opportunistic Fungi, Nematodes, and Plants

Plant-parasitic nematodes cause considerable harm to a variety of agricultural crops across the globe. Nematophagous bacteria, nematodes’ natural enemies, create traps to ensnare and eliminate the worms from the exterior. Others work as internal parasites, producing virulence factors and toxins that destroy the nematodes from the inside out. Opportunistic fungi are commonly employed as a biofungicide and to boost the plant’s defence system against diseases. They are primarily found in soil, tree bark, and on wild mushrooms. They have the ability to kill other fungus and enter plant roots. These fungus help plants develop and become more resilient to stress, among other positive impacts, because of their intimate associations with roots. The fungal secreted proteins in root–microbe interactions (both beneficial and detrimental) assist the development of contact with the roots, fungal attachment, root penetration, and the triggering of plant reactions. When plants interact with trichoderma roots, mechanisms such as oxidative bursts (ROS), salicylic acid synthesis, and secretion of elicitor-like proteins stimulate plant immunity and help prevent subsequent invasion by pests and pathogens. Plants and their associated microorganisms produce specialised metabolites that are vital to several biological processes that regulate the behaviour of neighbouring species. Understanding the functional role of specialised metabolites in the rhizosphere and their chemical composition is essential to understanding interactions within this subterranean ecosystem. Having uncovered the molecular foundations of disease resistance mechanisms, a rational crop protection strategy may now be developed. We reviewed recent advances in our understanding of the interactions among opportunistic fungi, nematodes, and plants in this chapter, with a focus on the molecular phenomena by which opportunistic fungi infect nematodes as well as on the nematode defence against pathogenic attacks around rhizosphere.