Alternative Management of Wheat Leaf Rust Caused by Puccinia triticina Revealing Histological and Biochemical Defense Mechanisms

Worldwide wheat production is seriously threatened due to infection by wheat leaf rust caused by Puccinia triticina. This study assessed the effectiveness of four tested treatments e.g. Bio-Arc, Bion, Frankincense oil and Cyanobacteria against the wheat leaf rust under greenhouse conditions on seedling and adult stages, as well as the mechanisms underlying disease resistance. Compared to other treatments, the application of Bion and Frankincense oil inhibited spore germination and increased incubation and latent periods. Moreover, had the least infection type, pustule size, and the number of pustules cm2, decreased the incidence of leaf rust infection (final rust severity%, rate of disease increase, and area under disease progress curve) and was effective up to 73.85 and 88.9% at the seedling and adult stage, respectively, compared to the untreated control. Bio-Arc's treatment had a moderate efficacy of 50 and 47.23%, respectively. While, Cyanobacteria was the least one in their effect. Using scanning electron microscope; abnormalities were observed in treated leaves, including urediniospore lysis, collapse, and shrinkage in four tested treatments. Treatments led to a significant increase in the activities of antioxidant defense enzymes, specifically catalase (CAT), peroxidase (POX), and polyphenol oxidase (PPO). GC-MS analysis used with the treated wheat leaves by four treatments, identified 41 compounds that were identified at different rotation times as the active organic compounds.