Characterization of a Hypersensitive Response-Induced Gene TaHIR3 from Wheat Leaves Infected with Leaf Rust

Hypersensitive-induced reaction (HIR) proteins and more specific members of the proliferation, ion and death superfamily participate in response to pathogen attacks and development of spontaneous hypersensitive lesions in maize and barley leaves. In the present study, a full-length TaHIR3 (1,246-bp) was cloned and characterized from wheat near-isogenic line Thatcher-Lr15 infected by Puccinia triticina isolate 05-19-43② through a homology cloning strategy. A 4,203-bp sequence of TaHIR3 including five exons was also obtained from wheat Thatcher-Lr15 genomic DNA. TaHIR3 shared higher similarity with HIR3 isolated from wheat, barley, and maize. Gene expression of TaHIR3 was spatially measured in young wheat leaves, young roots, young stems, mature seeds, and temporally in wheat leaves inoculated with virulent and avirulent P. triticina. TaHIR3 was expressed in all samples except mature seeds and was upregulated in both combinations. More transcripts accumulated in the incompatible than compatible combination, implying a role in wheat growth and resistance to pathogens attack. A polyclonal antibody was prepared with recombinant protein purified from a prokaryotic expression system with the open reading frame of TaHIR3, and it detected the target protein in wheat leaves by Western blotting. Detection results at the protein level also showed that TaHIR3 was upregulated expression in wheat leaves infected with the leaf rust pathogen. Characterization of TaHIR3 and its expression profiles at the DNA and protein levels suggest that TaHIR3 and its deduced protein play a role in wheat HR causing by the leaf rust pathogen.