TGA class II transcription factors are essential to restrict oxidative stress in response to UV-B stress in Arabidopsis
Keywords: rabidopsis, glutathione S-transferase, GSTU7, photooxidative stress, redox signaling, ROS, TGA class II, TGA2, transcription factor, UV-B stress
Plants possess a robust metabolic network for sensing and controlling reactive oxygen species (ROS) levels upon stress conditions. Evidence shown here supports a role for TGA class II transcription factors as critical regulators of genes controlling ROS levels in the tolerance response to UV-B stress in Arabidopsis. First, tga256 mutant plants showed reduced capacity to scavenge H2O2 and restrict oxidative damage in response to UV-B, and also to methylviologen-induced photooxidative stress. The TGA2 transgene (tga256/TGA2 plants) complemented these phenotypes. Second, RNAseq followed by clustering and Gene Ontology term analyses indicate that TGA2/5/6 positively control the UV-B-induced expression of a group of genes with oxidoreductase, glutathione transferase, and glucosyltransferase activities, such as members of the glutathione S-transferase Tau subfamily (GSTU), which encodes peroxide-scavenging enzymes. Accordingly, increased glutathione peroxidase activity triggered by UV-B was impaired in tga256 mutants. Third, the function of TGA2/5/6 as transcriptional activators of GSTU genes in the UV-B response was confirmed for GSTU7, GSTU8, and GSTU25, using quantitative reverse transcription–PCR and ChIP analyses. Fourth, expression of the GSTU7 transgene complemented the UV-B-susceptible phenotype of tga256 mutant plants. Together, this evidence indicates that TGA2/5/6 factors are key regulators of the antioxidant/detoxifying response to an abiotic stress such as UV-B light overexposure.
|Título de la Revista:||JOURNAL OF EXPERIMENTAL BOTANY|
|Editorial:||OXFORD UNIV PRESS|
|Fecha de publicación:||2020|
|Página de inicio:||1891|
|Financiamiento/Sponsor:||The authors thank Xin Li (Department of Botany, University of British Columbia, Canada) for providing the tga6-1, tga2-1 tga5-1, and tga2-1 tga5-1 tga6-1 mutant lines. This work was supported by the National Commission for Science and Technology CONICYT (|