A Puccinia striiformis f. sp. tritici effector inhibits the high-temperature seedling-plant resistance in wheat
Yangshan Hu, Chang Su, Yue Zhang, Yuxiang Li, Xianming Chen, Hongsheng Shang and Xiaoping Hu
Plant Journal
https://doi.org/10.1111/tpj.15945
Abstract
Resistance to Pseudomonas syringae pv. maculicola 1 (RPM1)-induced protein kinase (RIPK) in Arabidopsis belongs to the receptor-like cytoplasmic kinase (RLCK) family and plays a vital role in immunity. However, the role of RLCKs in the high-temperature seedling-plant (HTSP) resistance of wheat to Puccinia striiformis f. sp. tritici (Pst), the stripe rust pathogen, remains unclear. Here, we identified a homologous gene of RIPK in wheat, namely TaRIPK. The expression level of TaRIPK was induced by Pst-inoculation and high temperatures. Silencing TaRIPK reduced the expression level of TaRPM1, resulting in the weakness of HTSP resistance. Moreover, TaRIPK interacts with and phosphorylates papain-like cysteine protease 1 (TaPLCP1). Meanwhile, we found a Pst secreted protein PSTG_01766 targets TaPLCP1. Transient expression of PSTG_01766 inhibited basal immunity in tobacco and wheat. PSTG_01766 as an effector involved in the HTSP resistance was further supported by host-induced gene silencing, bacterial type three secretion system-mediated delivery into wheat, and enabled to inhibit of the TaRIPK-induced phosphorylation of TaPLCP1. Furthermore, PSTG_01766 has the potential to influence the subcellular localization of TaPLCP1. Overall, we suggest TaRIPK-TaPLCP1-TaRPM1 may fit the guard model to participate in the HTSP resistance. PSTG_01766 inhibits the HTSP resistance via targeting TaPLCP1. Guarded by wheat and attacked by Pst, TaPLCP1 may serve as a central hub of defense response. Our findings improve the understanding of the molecular mechanism of wheat HTSP resistance, which appears to be an essential strategy for controlling stripe rust with global warming.