A PR1-Like Protein Stabilizes a Barwin-Like Protein to Enhance Wheat Resistance to Leaf Rust

Pathogenesis-related 1 (PR1) proteins contribute to plant immunity through antimicrobial activity and the regulation of target protein stability and condensation. In wheat, TaPR1-2 has been widely used as a molecular marker of immune responses to rust fungi. However, it remains unclear whether other members of the PR1 family are involved in wheat resistance to leaf rust. Here, we show that the transcript levels of TaPR1-11 are induced following inoculation with Puccinia triticina (Pt). Overexpression of TaPR1-11 significantly enhanced wheat resistance to Pt, accompanied by reduced fungal growth, whereas TaPR1-11-RNAi wheat lines displayed increased susceptibility. TaPR1-11 physically interacts with TaPR4-1, a Barwin-like protein that also positively regulates wheat resistance to Pt. Further analysis revealed that TaPR1-11 stabilizes TaPR4-1 in vivo, while TaPR4-1 reciprocally promotes TaPR1-11 protein accumulation during Pt infection. Collectively, our findings identify a previously unreported PR1-PR4 protein partnership in wheat, showing that TaPR1-11 stabilizes TaPR4-1 to enhance resistance against Pt. This work expands current understanding of the molecular mechanisms by which PR1 proteins contribute to wheat defence responses.