Pluronic Gel System: An Approach to Investigate Chemotaxis of Plant Parasitic Nematodes

Cheomtaxis is the most important mechanism for host-localization of plant-parasitic nematodes.In this review, we discuss the research advances of chemotaxis of plant-parasitic nematodes to plant and potential chemicals from root rhizosphere. We introduce that one transparent thermos-reversible Pluronic gel simulates soil three-dimensional way to allow nematodes move freely in the gel and currently the gel is the best medium to study nematode behavior and chemotaxis. Through this gel system, root-knot nematodes were found to prefer to gather together at low pH (pH range 4.5~5.4); the attraction of CO₂ to nematodes was not due to CO₂ itself but due to acidification of solutions by dissolved CO₂ in the gel; nematodes formed clumps at low concentration of HCN (15 μM~22 μM) and the clumping gene was mapped to nematode genome; ethylene signal pathway modulated nematode attraction. In addition, ascarosides as conserved nematode signaling molecules eliciting plant defenses and pathogen resistance also involved in nematode aggregation and clumping. Current research hotspot is to identify semiochemicals from root or nematode exuduates which modify or regulate nematode chemotaxis.