The potential of dimetindene maleate inducing resistance to blast fungus Magnaporthe oryzae through activating the salicylic acid signaling pathway in rice plants.

BACKGROUND: Rice blast disease (Magnaporthe oryzae) is considered the most destructive rice disease all over the world. Dimetindene maleate is used in medication against allergic reactions in humans. Dimetindene maleate used to induce systemic acquired resistance (SAR) in rice (Oryza sativa L.) in order to protect rice plants from blast disease. RESULTS: Dimetindene maleate was not effective against fungus linear growth in vitro. In glasshouse conditions, dimetindene maleate significantly improved resistance at 25, 50, 125, 250, 500 and 1000 mg L-1 concentrations. Leaf blast severity reached 14.18% on plants treated with the most effective concentration of 125 mg L-1 compared with control plants. In field conditions during both seasons (2016 and 2017), 125 mg L-1 dimetindene maleate decreased the disease severity to 1.1% and 2.7%, respectively, after 30 days of treatment. Also, grain yield was increased to 13.27 and 12.90 t ha-1 in 2016 and 2017 seasons, respectively. Moreover, dimetindene maleate induces some of the indicators for salicylic acid and jasmonic acid pathways via gene expression. These genes include OsWRKY45, OsNPR1, AOS2, JAMYB and PBZ1 (OsPR10), recording 15.14-, 16.47-, 5.3-, 5.37- and 5.1-fold changes, respectively, 12-h postinoculation. CONCLUSION: The results overview investigated the effectiveness of dimetindene maleate for increasing rice resistance to blast disease through inducing SAR in rice plants under glasshouse and field conditions, which could be through the SA defense pathway by expression of genes (OsWRKY45 and OsNPR1). © 2021 Society of Chemical Industry.

Durability of Adult Plant Resistance Gene Yr18 in Partial Resistance Behavior of Wheat (Triticum aestivum) Genotypes with Different Degrees of Tolerance to Stripe Rust Disease, Caused by Puccinia striiformis f. sp. tritici: A Five-Year Study.

Adult plant resistance in wheat is an achievement of the breeding objective because of its durability in comparison with race-specific resistance. Partial resistance to wheat stripe rust disease was evaluated under greenhouse and field conditions during the period from 2016 to 2021. Misr 3, Sakha 95, and Giza 171 were the highest effective wheat genotypes against Puccinia striiformis f. sp. tritici races. Under greenhouse genotypes, Sakha 94, Giza 168, and Shandaweel1 were moderately susceptible, had the longest latent period and lowest values of the length of stripes and infection frequency at the adult stage. Partial resistance levels under field conditions were assessed, genotypes Sakha 94, Giza 168, and Shandaweel1 exhibited partial resistance against the disease. Leaf tip necrosis (LTN) was noted positively in three genotypes Sakha 94, Sakha 95, and Shandaweel1. Molecular analyses of Yr18 were performed for csLV34, cssfr1, and cssfr2 markers. Only Sakha 94 and Shandaweel1 proved to carry the Yr18 resistance allele at both phenotypic and genotypic levels. Scanning electron microscopy (SEM) observed that the susceptible genotypes were colonized extensively on leaves, but on the slow-rusting genotype, the pustules were much less in number, diminutive, and poorly sporulation, which is similar to the pustule of NIL Jupateco73 'R'.