Guan Qijie, David Lisa, Moran Riley, Grela Ivan, Ortega Angelica, Scott Peter, Warnock Lindsey, Chen Sixue
Department of Biology, University of Mississippi, Oxford, MS 38677, USA.
Department of Biology, University of Florida, Gainesville, FL 32611, USA.
Plants (Basel). 2023 May 29;12(11):2137. doi: 10.3390/plants12112137.
Stomatal immunity is the primary gate of the plant pathogen defense system. Non-expressor of Pathogenesis Related 1 (NPR1) is the salicylic acid (SA) receptor, which is critical for stomatal defense. SA induces stomatal closure, but the specific role of NPR1 in guard cells and its contribution to systemic acquired resistance (SAR) remain largely unknown. In this study, we compared the response to pathogen attack in wild-type Arabidopsis and the knockout mutant in terms of stomatal movement and proteomic changes. We found that NPR1 does not regulate stomatal density, but the mutant failed to close stomata when under pathogen attack, resulting in more pathogens entering the leaves. Moreover, the ROS levels in the mutant were higher than in the wild type, and several proteins involved in carbon fixation, oxidative phosphorylation, glycolysis, and glutathione metabolism were differentially changed in abundance. Our findings suggest that mobile SAR signals alter stomatal immune response possibly by initiating ROS burst, and the mutant has an alternative priming effect through translational regulation.
气孔免疫是植物病原体防御系统的主要关卡。病程相关蛋白1非表达子（NPR1）是水杨酸（SA）受体，对气孔防御至关重要。SA诱导气孔关闭，但NPR1在保卫细胞中的具体作用及其对系统获得性抗性（SAR）的贡献仍 largely未知。在本研究中，我们比较了野生型拟南芥和敲除突变体在气孔运动和蛋白质组变化方面对病原体攻击的反应。我们发现NPR1不调节气孔密度，但突变体在病原体攻击时未能关闭气孔，导致更多病原体进入叶片。此外，突变体中的活性氧水平高于野生型，并且参与碳固定、氧化磷酸化、糖酵解和谷胱甘肽代谢的几种蛋白质在丰度上有差异变化。我们的研究结果表明，移动的SAR信号可能通过引发活性氧爆发来改变气孔免疫反应，并且突变体通过翻译调控具有替代的引发效应。
