Plants possess a diversity of Reactive Oxygen Species (ROS)-processing enzymes involved in sensing and controlling ROS levels under basal and stressful conditions. There is little information on the transcriptional regulators that control the expression of these ROS-processing enzymes, particularly at the onset of the defense response to abiotic stress. Filling this gap, this paper reports a critical role for Arabidopsis TGA class II factors (TGA2, TGA5, and TGA6) in the tolerance response to UV-B light and photooxidative stress, by activating the expression of genes with antioxidative roles. We identified two clusters of genes responsive to UV-B and activated by TGA2/5/6 were identified using RNAseq and clustering analysis. The GSTU gene family, which encodes glutathione transferase enzymes from the Tau subclass, was overrepresented in these clusters. We corroborated the TGA2-mediated activation in response to UV-B for three model genes (GSTU7, GSTU8, and GSTU25) using RT-qPCR and ChIP analyses. Interestingly, using tga256 mutant and TGA2- and GSTU7-complemented mutant plants, we demonstrated that TGA2-mediated induction of GSTU genes is essential to control ROS levels and oxidative damage after UV-B and MeV treatments. This evidence positions TGA class II factors, particularly TGA2, as a key players in the redox signaling network of Arabidopsis plants.

中文翻译：

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转录因子TGA2对于拟南芥中UV-B胁迫耐受性控制氧化胁迫至关重要

植物具有多种在基础和胁迫条件下参与传感和控制ROS水平的活性氧（ROS）处理酶。关于控制这些ROS处理酶表达的转录调节因子的信息很少，尤其是在对非生物胁迫的防御反应开始时。填补这一空白，本文报道了拟南芥TGA II类因子（TGA2，TGA5和TGA6）在通过激活具有抗氧化作用的基因的表达而对UV-B光和光氧化胁迫的耐受性中的关键作用。我们使用RNAseq和聚类分析确定了对UV-B有响应并被TGA2 / 5/6激活的两个基因簇。GSTU基因家族，它编码来自Tau亚类的谷胱甘肽转移酶，在这些集群中人数过多。我们证实了TGA2介导的针对三个模型基因的UV-B激活（GSTU7，GSTU8和GSTU25），使用RT-qPCR和ChIP分析。有趣的是，使用tga256突变体以及TGA2和GSTU7互补的突变植物，我们证明了TGA2介导的GSTU基因的诱导对于控制ROS水平和UV-B和MeV处理后的氧化损伤至关重要。该证据将TGA II类因子（尤其是TGA2）定位为拟南芥植物氧化还原信号网络中的关键角色。