Ultraviolet-B Irradiation Induces Resistance against Powdery Mildew in Cucumber (Cucumis sativus L.) through a Different Mechanism Than That of Heat Shock-Induced Resistance

Heat shock treatment (HST) and UV-B irradiation can reduce pathogen infection in crops. However, information on the mechanism of action is limited. Here, we investigated UV-B-induced resistance against powdery mildew cucumber compared it to that heat-shock-induced resistance. We measured percentage leaf area showing disease symptoms examined expression levels defense- heat-shock-related genes across groups. (intensity, 5 µW/cm2) for 4 h/d followed by inoculation reduced appearance 21.17% with control group. Unlike HST—which induces systemic resistance—UV-B induced local cucumber, as indicated changes gene (Chi2 ETR2). UV-B-treated plants inoculated showed higher Chi2, ETR2, LOX6 than were either treated or inoculated. had no major effects acquired heat transcription factors, which are known be affected HST. Combined HST a strong synergistic effect reducing cucumber. Our results indicate likely operates through different triggering infection.