Genes involved in adult plant resistance to stripe rust in wheat cultivar Xingzi 9104

Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a destructive disease of wheat (Triticum aestivum) worldwide. Adult plant resistance to stripe rust resistance in wheat is often durable. To gain a better understanding of the mechanism of adult plant resistance, a suppressive subtractive hybridization (SSH) approach was used to identify wheat genes induced by Pst infection at the adult plant stage. Based on the putative functions of 436 SSH-derived unigene sequences, we characterized defense responses triggered during infection and development of adult plant resistance in wheat cultivar Xingzi 9104. Eighty nine genes were found to be involved in defense and signal transduction. Twelve of the genes were selected for time-course expression analyses using quantitative RT-PCR. Nine of those genes were induced by Pst infection, including those predicted to encode peroxidase, BAX inhibitor, Concanavalin A-like lectin/glucanase, subtilisin-chymotrypsin inhibitor, chinase, glucan endo-1,3-beta-D-glucosidase and acidic PR5 precursor. We found that some PR protein genes kept high expression levels longer in the adult plants than in seedlings after Pst infection. This study is the first to report a concanavalin A-like lectin/glucanase involved in plant defense against pathogen infection. The large number of genes obtained through constructing the SSH library are valuable for further studies to achieve a better understanding of molecular mechanisms of stripe rust resistance in wheat and also useful for studying resistance mechanisms in other plant pathosystems.

► A series of genes differentially expressed during Pst infection of wheat XZ.
► Expression profiling was deciphered through gene annotation and characterization.
► Rapid and long-lasting expression of PR genes in adult XZ was observed.
►  Some genes specifically expressed in inoculated adult XZ plants were identified.