The RLK protein TaCRK10 activates wheat high‐temperature seedling‐plant resistance to stripe rust through interacting with TaH2A.1.

SUMMARY: Plants sense various pathogens and activate immunity responses through receptor‐like kinases (RLKs). Cysteine‐rich receptor‐like kinases (CRKs) are involved in massive transduction pathways upon perception of a pathogen. However, the roles of CRKs in response to stripe rust are unclear. In the present study, we identified a CRK gene (designated TaCRK10) from wheat variety Xiaoyan 6 (XY6) that harbors high‐temperature seedling‐plant (HTSP) resistance to stripe rust caused by fungal pathogen Puccinia striiformis f. sp. tritici (Pst). The expression level of TaCRK10 was induced by Pst inoculation and high temperature treatment. Knockdown of TaCRK10 by virus‐induced gene silencing resulted in attenuated wheat HTSP resistance to Pst, whereas there is no effect on Pst development and host responses under normal temperatures. Notably, overexpression of TaCRK10 in susceptible variety Fielder provided resistance only under normal temperatures at 14 days with reactive oxygen species accumulation and defense‐related gene expression of the salicylic acid pathway. Moreover, TaCRK10 physically interacted with and phosphorylated a histone variant TaH2A.1, which belongs to the H2A.W group. Silencing of TaH2A.1 suppressed wheat resistance to Pst, indicating that TaH2A.1 plays a positive role in wheat resistance to Pst. Thus, TaCRK10 serves as an important sensor of Pst infection and high temperatures, and it activates wheat resistance to Pst through regulating nuclear processes. This knowledge helps elucidate the molecular mechanism of wheat HTSP resistance to Pst and promotes efforts in developing wheat varieties with resistance to stripe rust. Significance Statement: Wheat high‐temperature seedling‐plant (HTSP) resistance to Puccinia striiformis f. sp. tritici (Pst) is non‐race specific and is induced by exposure of wheat plants to high temperatures. Here, high temperature treatment and Pst inoculation induced the high expression of TaCRK10, which activates wheat resistance to Pst through interacting with and phosphorylating a histone variant TaH2A.1 that belongs to the H2A.W group. Overexpression of TaCRK10 in susceptible variety Fielder provided resistance only under normal temperatures. These findings can elucidate the molecular mechanism of wheat HTSP resistance to Pst, and will make contributions to improving and utilizing this kind of resistance. [ABSTRACT FROM AUTHOR]

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