Plants recognize pathogens and activate immune responses, which usually involve massive transcriptional reprogramming. The evolutionarily conserved kinase, Sucrose non-fermenting-related kinase 1 (SnRK1), functions as a metabolic regulator that is essential for plant growth and stress responses. Here, we identify barley SnRK1 and a WRKY3 transcription factor by screening a cDNA library. SnRK1 interacts with WRKY3 in yeast, as confirmed by pull-down and luciferase complementation assays. Förster resonance energy transfer combined with noninvasive fluorescence lifetime imaging analysis indicates that the interaction occurs in the barley nucleus. Transient expression and virus-induced gene silencing analyses indicate that WRKY3 acts as a repressor of disease resistance to the Bgh fungus. Barley plants overexpressing WRKY3 have enhanced fungal microcolony formation and sporulation. Phosphorylation assays show that SnRK1 phosphorylates WRKY3 mainly at Ser83 and Ser112 to destabilize the repressor, and WRKY3 non-phosphorylation-null mutants at these two sites are more stable than the wild-type protein. SnRK1-overexpressing barley plants display enhanced disease resistance to Bgh. Transient expression of SnRK1 reduces fungal haustorium formation in barley cells, which probably requires SnRK1 nuclear localization and kinase activity. Together, these findings suggest that SnRK1 is directly involved in plant immunity through phosphorylation and destabilization of the WRKY3 repressor, revealing a new regulatory mechanism of immune derepression in plants.

植物识别病原体并激活免疫反应，这通常涉及大规模的转录重编程。进化上保守的激酶，蔗糖非发酵相关激酶 1 (SnRK1)，作为一种代谢调节剂，对植物生长和应激反应至关重要。在这里，我们通过筛选 cDNA 文库来鉴定大麦 SnRK1 和 WRKY3 转录因子。SnRK1 与酵母中的 WRKY3 相互作用，通过下拉和荧光素酶互补测定证实。Förster 共振能量转移结合无创荧光寿命成像分析表明相互作用发生在大麦核中。瞬时表达和病毒诱导的基因沉默分析表明 WRKY3 作为对Bgh抗病性的抑制因子菌。过表达WRKY3 的大麦植物具有增强的真菌微菌落形成和孢子形成。磷酸化分析表明，SnRK1 主要在 Ser83 和 Ser112 位点磷酸化 WRKY3，使阻遏物不稳定，这两个位点的 WRKY3 非磷酸化无效突变体比野生型蛋白更稳定。SnRK1 过表达的大麦植物对Bgh 的抗病性增强。SnRK1 的瞬时表达减少了大麦细胞中真菌吸器的形成，这可能需要 SnRK1 核定位和激酶活性。总之，这些发现表明 SnRK1 通过 WRKY3 抑制子的磷酸化和去稳定直接参与植物免疫，揭示了植物免疫去抑制的新调节机制。