INDUCTION OF SYSTEMIC RESISTANCE AGAINST MELOIDOGYNE INCOGNITA BY DIFFERENT CHEMICAL AND BIOLOGICAL INDUCERS IN TOMATO PLANTS

Root-knot, caused by Meloidogyne incognita, is a soilborne disease that causes severe damage and large losses in tomato production worldwide. For this reason, biological and chemical elicitors of induced resistance were examined for their ability to protect tomato from root-knot disease under glasshouse conditions. Treatment of tomato roots with B. thuringiensis as a soil drench resulted in the highest reduction in the number of galls in root system, while the nematicide Rugby (R) 20% CS and salicylic acid (SA) showed the highest reduction in egg-masses and nematode populations. Moreover, pre-treatment of tomato roots with silica nanoparticies (SINPs) exhibited the highest increase in the shoot fresh and dry weights. The activities of defence related enzymes, peroxidase (PDX) and polyphenol oxidase (PPO), were significantly increased in treated tomato plants, SA and ascorbic acid treatments showed the best results in this respect. The best transcription level of SA-inducible gene PR2 was found in SA treated tomato plants followed by the Allium sativum extract treatment. Therefore, B. Thuringiensis, SA and SINPs could provide new alternatives for chemical pesticides in integrated pest management strategies against root-knot diseases that cause synergistic yield losses.