Enhanced autoimmunity often leads to impaired plant growth and development, and the coordination of immunity and growth in Populus remains elusive. In this study, we have identified the transcription factors PagWRKY33a/b as key regulators of immune response and growth maintenance in Populus. The disruption of PagWRKY33a/b causes growth issues and autoimmunity while conferring resistance to anthracnose caused by Colletotrichum gloeosporioides. PagWRKY33a/b binds to the promoters of N requirement gene 1.1 (NRG1.1) and Gibberellic Acid-Stimulated in Arabidopsis (GASA14) during infection, activating their transcription. This process maintains disease resistance and engages in GA signaling to reduce growth costs from immune activation. The oxPagWRKY33a/nrg1.1 mutant results in reduced resistance to C. gloeosporioides. Further, PagWRKY33a/b is phosphorylated and activated by mitogen-activated protein kinase kinase 1, which inhibits respiratory burst oxidase homolog D (RBOHD) and respiratory burst oxidase homolog I (RBOHI) transcription, causing reactive oxygen species bursts in wrky33a/b double mutants. This leads to an upregulation of PagNRG1.1 in the absence of pathogens. However, the wrky33a/b/nrg1.1 and wrky33a/b/rbohd triple mutants show compromised defense responses, underscoring the complexity of WRKY33 regulation. Additionally, the stability of PagWRKY33 is modulated by Ring Finger Protein 5 (PagRNF5)-mediated ubiquitination, balancing plant immunity and growth. Together, our results provide key insights into the complex function of WRKY33 in Populus autoimmunity and its impact on growth and development.

中文翻译：

---

转录因子 PagWRKY33 调节杨树赤霉素信号传导和免疫受体通路


增强的自身免疫通常会导致植物生长发育受损，而杨树免疫力和生长的协调仍然难以捉摸。在这项研究中，我们确定了转录因子 PagWRKY33a/b 是杨树免疫反应和生长维持的关键调节因子。PagWRKY33a/b 的破坏会导致生长问题和自身免疫，同时赋予对胶孢炭疽菌引起的炭疽病的抵抗力。PagWRKY33a/b 在感染过程中与 N 需求基因 1.1 （NRG1.1） 和拟南芥赤霉酸刺激 （GASA14） 的启动子结合，激活它们的转录。这个过程保持抗病性并参与 GA 信号传导，以降低免疫激活的生长成本。oxPagWRKY33a/nrg1.1 突变体导致对 C. gloeosporioides 的抗性降低。此外，PagWRKY33a/b 被丝裂原活化蛋白激酶 1 磷酸化和激活，抑制呼吸爆发氧化酶同源物 D （RBOHD） 和呼吸爆发氧化酶同源物 I （RBOHI） 转录，导致 wrky33a/b 双突变体中的活性氧爆发。这导致 PagNRG1.1 在没有病原体的情况下上调。然而，wrky33a/b/nrg1.1 和 wrky33a/b/rbohd 三重突变体显示出受损的防御反应，强调了 WRKY33 调控的复杂性。此外，PagWRKY33 的稳定性受无名指蛋白 5 （PagRNF5） 介导的泛素化调节，平衡植物免疫和生长。总之，我们的结果为 WRKY33 在杨树自身免疫中的复杂功能及其对生长和发育的影响提供了关键见解。