Six different abiotic elicitors (oxalic acid, potassium oxalate, salicylic acid, Bion, Fungastop and Photophor) were used to study their effect on induced resistance of cucumber (Cucumis sativus L.) against powdery mildew (Sphaerotheca fuliginea) disease. The inducers efficiency was evaluated depending on disease severity calculation and measure the biochemical change in both pathogensis Related Protein (PR) and phytoalexin accumulation in treated plants comparing with the control. Pretreatment of cucumber plants with all tested elicitors recorded a decrease in powdery mildew disease severity. Bion recorded the most effective inducers (63.8 and 72.4%) while potassium oxalate recorded the lowest effective one (37.0 and 58.3%) in both single and booster spray. Induced resistance of cucumber against powdery mildew recorded an increase in PR-proteins (peroxidase, polyphenoloxidase, Chitinase and β-1, 3 glucanase) activity as well as an increase accumulation of phytoalexins. Application of abiotic agents in these experiments enhances the induced resistance in cucumber against powdery mildew. It would therefore be the proposal to use abiotic inducers as alternatives to the fungicides and one of a wide range of disease management tools.
Muneera Alkahtani, S.A. Omer, M.A. El-Naggar, Eman M. Abdel-Kareem and M.A. Mahmoud, 2011. Pathogenesis-related Protein and Phytoalexin Induction against Cucumber Powdery Mildew by Elicitors. International Journal of Plant Pathology, 2: 63-71.