Arabidopsis (Arabidopsis thaliana) OXIDATION RESISTANCE2 (AtOXR2) is a mitochondrial protein belonging to the Oxidation Resistance (OXR) protein family, recently described in plants. We analyzed the impact of AtOXR2 in Arabidopsis defense mechanisms against the hemibiotrophic bacterial pathogen Pseudomonas syringae. oxr2 mutant plants are more susceptible to infection by the pathogen and, conversely, plants overexpressing AtOXR2 (oeOXR2 plants) show enhanced disease resistance. Resistance in these plants is accompanied by higher expression of WRKY transcription factors, induction of genes involved in salicylic acid (SA) synthesis, accumulation of free SA, and overall activation of the SA signaling pathway. Accordingly, defense phenotypes are dependent on SA synthesis and SA perception pathways, since they are lost in isochorismate synthase1/salicylic acid induction deficient2 and nonexpressor of pathogenesis-related genes1 (npr1) mutant backgrounds. Overexpression of AtOXR2 leads to faster and stronger oxidative burst in response to the bacterial flagellin peptide flg22. Moreover, AtOXR2 affects the nuclear localization of the transcriptional coactivator NPR1, a master regulator of SA signaling. oeOXR2 plants have increased levels of total glutathione and a more oxidized cytosolic redox cellular environment under normal growth conditions. Therefore, AtOXR2 contributes to establishing plant protection against infection by P. syringae acting on the activity of the SA pathway.

拟南芥（ Arabidopsis thaliana ）氧化抵抗2（AtOXR2）是一种线粒体蛋白，属于氧化抵抗（OXR）蛋白家族，最近在植物中得到描述。我们分析了 AtOXR2 在拟南芥防御半生物营养型细菌病原体丁香假单胞菌的防御机制中的影响。 oxr2突变植物更容易受到病原体的感染，相反，过度表达AtOXR2 的植物（oeOXR2 植物）表现出增强的抗病性。这些植物中的抗性伴随着 WRKY 转录因子的较高表达、参与水杨酸 (SA) 合成的基因的诱导、游离 SA 的积累以及 SA 信号通路的整体激活。因此，防御表型依赖于 SA 合成和 SA 感知途径，因为它们在异分支酸合酶 1 /水杨酸诱导缺陷 2和发病机制相关基因 1 ( npr1 ) 突变体非表达背景中丢失。 AtOXR2 的过度表达会导致细菌鞭毛蛋白肽flg22产生更快更强的氧化爆发。此外，AtOXR2 影响转录共激活因子 NPR1（SA 信号传导的主要调节因子）的核定位。 oeOXR2植物在正常生长条件下具有增加的总谷胱甘肽水平和氧化程度更高的胞质氧化还原细胞环境。因此，AtOXR2 有助于建立植物保护机制，防止丁香假单胞菌感染，作用于 SA 途径的活性。