State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Innovation Academy for Seed Design, Beijing 100101, China.
CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.
Plant Commun. 2020 Jun 9;1(4):100083. doi: 10.1016/j.xplc.2020.100083. eCollection 2020 Jul 13.
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 fungus. Barley plants overexpressing 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 . 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.
植物可以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 Sucrose non-fermenting-related kinase 1（SnRK1）作为一种代谢调节剂，对于植物的生长和应激反应是必不可少的。在这里，我们通过筛选 cDNA 文库鉴定了大麦 SnRK1 和一个 WRKY3 转录因子。SnRK1 在酵母中与 WRKY3 相互作用，这一点通过下拉和荧光素酶互补测定得到了证实。荧光共振能量转移结合非侵入性荧光寿命成像分析表明，这种相互作用发生在大麦的细胞核中。瞬时表达和病毒诱导的基因沉默分析表明，WRKY3 作为真菌抗病性的抑制剂发挥作用。过表达 的大麦植物增强了真菌微菌落的形成和孢子形成。磷酸化实验表明，SnRK1 主要在 Ser83 和 Ser112 处磷酸化 WRKY3 以使其不稳定，而这两个位点的 WRKY3 非磷酸化突变体比野生型蛋白更稳定。过表达 SnRK1 的大麦植物对 表现出增强的抗病性。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 的核定位和激酶活性。总之，这些发现表明 SnRK1 通过磷酸化和 WRKY3 抑制剂的失活直接参与植物免疫，揭示了植物免疫去阻遏的一种新的调节机制。
