Characterizing Resistance Genes in Wheat-Stem Rust Interaction

Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is one of the most important diseases of wheat with devastating epidemics in Iran and the world. In this study, we evaluated some Iranian wheat landraces in a greenhouse at the seedling stage against a new pathotype related to Ug۹۹ of Pgt, which was collected from Iran and designated as TTSSK. Marker analysis was done on resistant landraces. Molecular markers for detecting some Sr genes were used. The results showed that Sr۲۲, Sr۳۵ and SrWeb provided resistance against TTSSK in the resistant landraces. In addition, some of the susceptible landraces that were resistant at adult stage were used for Sr۲ analysis. The results showed that some of these landraces were carrying other adult plant resistance gene/genes except Sr۲. To evaluate the defence gene expression in compatible and incompatible interactions, cv. Morocco (susceptible) and KC-۴۴۰ landrace (resistant) were used. Sampling was done at ۰, ۱۲, ۱۸, ۲۴, and ۷۲ hours post inoculation (hpi) with stem rust isolate and water as mock treatment. β-۱,۳ glucanase gene expressions were studied using qGLU-S and qGLU-AS primers. Also, ۱۸srRNA, β-tubulin and EF۱-α genes were used as internal control. The results showed that in incompatible interactions, the defence gene expression was increased at ۲۴ hpi, but in compatible interactions, expression level reached the peak at ۱۲ hpi and it significantly decreased at ۱۸ hpi. The results revealed that the expression of defence genes such as β-۱,۳ glucanase was earlier in compatible interactions than in incompatible interactions, but the quantity of expressed gene was less than in incompatible interactions.

کلیدواژه ها:

β-۱ ، ۳ glucanase ، Real-time PCR ، Sr genes ، SSR marker ، Ug۹۹.