Plant parasitic nematodes cause an estimated US$80 to 157 billion in annual crop losses worldwide. The most economically important plant parasitic nematodes include root-knot nematodes from the genus Meloidogyne and cyst nematodes of the genera Heterodera and Globodera. Both root-knot nematodes and cyst nematodes, as sedentary endoparasites, penetrate the host root to establish a feeding site (a giant cell or syncytium), where they settle down and feed through subsequent sedentary life stages. Plants in turn use a sophisticated innate immune system to perceive and defend themselves against the invading nematodes. This project aims to address a key question related to plant resistance to nematodes: how do plants detect nematode-derived small-molecule signals, specifically ascaroside 18 (Ascr18), to activate their immune system and fight infection. Besides elucidating the mechanisms underlying potato resistance to the notorious potato cyst nematode Globodera pallida, this project will also support the training of high school, undergraduate and graduate students. By connecting cutting-edge molecular biology with real life agriculture problems, this project will motivate and engage students in plant biology research and inspire them to become the next generation of leading plant scientists. Plants have evolved pattern recognition receptors (PRRs), which detect pathogen-associated molecular patterns (PAMPs) as a basal layer of immune response to activate pattern-triggered immun