Chemosensory Pathways Involved in the Perception of Tomato-Derived Flavonoids and Alkaloids in Meloidogyne incognita

Plant-parasitic nematodes rely on the perception of host-derived chemical cues released from plant roots to locate suitable hosts, representing a critical prerequisite for successful plant infection. In this study, we selected four representative tomato (Solanum lycopersicum L.) root-derived chemical signals and demonstrated their distinct effects on the host-seeking behavior of the southern root-knot nematode (Meloidogyne incognita). Among these compounds, the flavonoids quercetin and luteolin exhibited significant attractant effects, whereas the alkaloids dihydrocapsaicin and solasodine showed repellent effects. RNA interference (RNAi) experiments further indicated that multiple chemosensory neurons are involved in the recognition of plant-derived chemical cues. Silencing of key chemosensory genes significantly impaired the directed chemotactic response of M. incognita toward tomato roots and reduced its infectivity, demonstrating that the chemosensory system represents a crucial molecular basis regulating host localization and parasitic establishment. This study provides new insights into host recognition mechanisms in root-knot nematodes and offers a theoretical foundation for developing environmentally sustainable strategies for nematode management by targeting host perception processes.