Role of Tomatidine as Resistant Factor in Solanum Lycopersicum (L.) against Meloidogyne Incognita (Kofoid and White) Chitwood

Tomatidine is the aglycon of tomato saponin β-tomatine implicated in host plant resistance against phytopathogens. Evaluation of the level of tomatidine in root, shoot and fruit of nematode resistant and susceptible tomatoes by liquid chromatography following root infection with root-knot nematode, Meloidogyne incognita in a plant growth chamber revealed a higher concentration of tomatidine in resistant cultivars (Hisar Lalit and PBNR-7) than the susceptible cultivar (Pusa Ruby). The tomatidine concentration in root and shoot decreased with increase of nematode inoculum from 2 to 4 J2 per gram growth medium and on maturity of fruit from green to red stage. Nematode infection in root triggered a decrease of tomatidine level in shoot as well. This might provide plant defense vide elevated synthesis of tomato defense glycoalkaloid a-tomatine.