TaHSP90 stabilizes Lr13 to regulate temperature-sensitive resistance to leaf rust in wheat seedlings

Escalating wheat leaf rust disease pressure under climate warming threatens global wheat production security, necessitating the development of durable leaf rust resistance as a strategy to counter emerging threats. Through transcriptomic analysis and histochemical staining, this study demonstrated that Lr13 induced higher levels of salicylic acid (SA) signaling and reactive oxygen species (ROS) accumulation at 25°C compared to 18°C. Using affinity purification coupled with mass spectrometry (AP-MS) and protein interaction assays, TaHSP90 was identified as a thermoregulatory Lr13-interacting protein during infection by the leaf rust pathogen Puccinia triticina (Pt). Lr13 bypassed 26S-proteasome-mediated degradation by combining with HSP90-RAR1, thus maintaining SA-related gene expression and ROS burst at the higher temperature. Our findings demonstrate that TaHSP90 positively regulates the temperature-sensitive leaf rust resistance conferred by Lr13 in wheat, offering strategic insights to combat rust diseases.