Immunization of tomato plants against root-knot nematode Meloidogyne incognita with biogenic elicitors

Mechanisms of induced tomato plant resistance to root-knot nematode were studied. The biogenic elicitor arachidonic acid, at concentrations of 0.1-10 mu M, was shown to ensure systemic, long-term protection against Meloidogyne incognita. plants grown from seeds treated with arachidonic acid were considerably less susceptible to this nematode over the entire vegetation period. The data showed that qualitative and quantitative changes in the composition of sterols and formation of the phytoalexin rishitin, which is toxic to nematodes, were likely to account for the protective effect.