INDUCED IMMUNE RESPONSE AGAINST POWDERY MILDEW DISEASE IN SUMMER SQUASH PLANT

Abstract

Powdery mildew (PM) is one of the common diseases responsible for limiting summer squash crops productivity in Egypt. So, Nitric oxide (NO) using for stimulating immune signaling molecule which was given as Sodium nitroprusside (SNP) in different concentrations (5, 7.5 and 10mM) for spraying summer squash foliar to induce pre immune response against PM. In general, in the three disease evaluations index, the 10mM SNP had the best result and the lowest decreasing in disease Index percentage and infected leaves number percentage. Then, the biochemical studies presented the reasons of 14d as incubation period, plant cell death in high levels of (H2O2, NO˙, ONOOˉ and MDA) and the conversion between 5 and 10mM SNP in first and second disease evaluations. So, the oxidative and nitrosative stresses responsible for increasing in The antioxidant system (Non enzymatic and enzymatic) which was affected on redox – based signaling and protein modification. Key words: summer squash immunity, powdery mildew, peroxynitrite, nitric oxide, hydrogen peroxide