Protein Profiling of Wheat Leaves Infected with Powdery Mildew and Treated with the Benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (BTH)

Systemic acquired resistance is an important component of the disease resistance repertoire of plants. A novel synthetic chemical, Benzo (1,2,3) thiadiazole-7-carbothioic acid S-methyl ester (BTH), was shown to induce acquired resistance in wheat. BTH protected wheat systemically against powdery mildew infection by affecting multiple steps in the life cycle of the pathogen. In this study, protein extracts from the whole leaves were analyzed on high resolution two-dimensional gels electrophoresis. The onset of resistance was accompanied by the induction of a newly described wheat and other plants chemically induced genes, including genes encoding a lipoxygenase, putative pollen specific protein, ATP binding/kinase/protein kinase, cysteine proteinase inhibitor clade B ovalbumin and selenium-binding protein-like. Compared with treated and untreated control plants, two proteins found in abundance under infection conditions were expressed and identified as β-1, 3-glucanase and glucan endo-1,3-β-D-glucosidase, a pathogenesis-related (PR-2) protein involved in protein degradation. Thus in infected powdery mildew of wheat, the increased β-1, 3-glucanase and glucan endo-1,3-β-D-glucosidase may play a part in the loss of proteins. Therefore, BTH was the most potent inducer of both resistance and gene induction.