Genes associated with resistance to wheat yellow rust disease identified by differential display analysis

Abstract

This study is focused on the identification of early response genes involved in the resistance mechanism of one of the most important diseases of wheat, yellow rust. The strategy undertaken was to use differential display reverse transcriptase-PCR method (DDRT-PCR) on two of the yellow rust differential lines of wheat, were infected with the virulent and the avirulent Puccinia striiformis f. sp. tritici races together with appropriate control inoculations. Upon infection of the plant materials (resistant and/or susceptible), different time points were evaluated on DDRT-PCR banding profiles. The expression level differences of 33 genes in DDRT-PCR were further analyzed using quantitative real-time PCR (qRT-PCR). Among which only those (14 gene fragments) resulting reproducible induction or repression levels were reported with measured fold changes. Based on the sequence similarity analysis, all but one were absent in NCBI databank, thus they are newly found wheat sequences. Among those, two genes were identified as full ORF, including 5′ and 3′ end untranslated regions (UTR); namely cyclophilin like protein (putative antifungal activity) and ubiquitin-conjugating enzyme (E2) or Rad6. The sequence homology analysis of the cloned gene fragments revealed that the genes detected may have roles in ubiquitinylation, programmed cell death (apoptosis), putative antifungal activities, disease resistance responses, pathogenesis related responses, and including a few with no known function.