Effects of the leaf rust pathogen on expression of TaHIR4 at the gene and protein levels in wheat

The hypersensitive response (HR) is one of the most-efficient forms of plant defense against biotrophic pathogens. However, the molecular mechanisms leading to HR remain largely unknown. A putative hypersensitive-induced response (HIR) protein gene TaHIR4 cDNA (919 bp) and a DNA sequence (2520 bp) including at least five exons were isolated and identified from wheat. Phylogenetic analysis showed that TaHIR4 was highly homologous to HvHIR4 from barley at both the cDNA and deduced amino-acid levels. Reverse transcription quantitative polymerase chain reaction (qRT-PCR) results showed that TaHIR4 transcripts were highly upregulated by infection of the leaf rust pathogen and expressed in all tested samples except the mature seeds. Western blotting results also showed that TaHIR4 protein was upregulated in wheat leaves infected with the leaf rust pathogen. Characterization and expression profiles at the gene and protein levels suggested that TaHIR4 plays a role in wheat HR, caused by the leaf rust pathogen.