Effect of temperature on resistance and biochemical changes in tomato inoculated with Meloidogyne incognita

Abstract

Resistance of VFN8 tomato seedlings to Meloidogyne incognita was measured at 27°C and 34°C by recording juvenile penetration, number of host necroses and galls. At temperature of 34°C resistance was reduced; the necrotic reaction was much less and many more galls developed on the roots than at 27°C. Polyphenoloxidase and peroxidase activity increased in the infested roots at 27°C, but not in infested roots grown at 34°C. Activity of an O2 generating system and lipid peroxidation increased at 27°C but decreased at 34°C. SOD and catalase activity were enhanced in inoculated roots at 34°C but remained unchanged at 27°e. It is suggested that the higher temperature induced disease susceptibility in the infested tomato roots because of a decline in superoxides and hydrogen peroxide consequent on the increased activity of SOD and catalase.