Grape (Vitis davidii) VdGATA2 functions as a transcription activator and enhances powdery mildew resistance via the active oxygen species pathway

The GATA transcription factor, composed of a type IV zinc finger (CX2CX17-20CX2C) and a highly alkaline region widely distributed in eukaryotes. In plants, nearly 30 plant GATA factors can be subdivided into four conservative and distinct groups: classes A through D. The first, AGTAs, were mainly studied in model plants, so our knowledge of them in grape species is quite limited. In this study, an A-GATA transcription factor, VdGATA2, isolated and characterized in Vitis davidii Tangwei which was found to contain one CX2CX18CX2C zinc finger in its C-terminal. The accumulation of VdGATA2 was rapidly induced by exogenous hormones and pathogens in grape. Transgenic VdGATA2 plants showed significantly improved resistance to powdery mildew disease. In transgenic Arabidopsis plants, the number of conidia of powdery mildew decreased compared with the wild Arabidopsis while the expression of PR1, the key gene in salicylic acid (SA) pathway, the concentration of hydrogen peroxide (H2O2), and the catalase (CAT) enzyme activity all increased. After methyl viologen (MV), the contents of H2O2 and malondialdenyde (MDA) reduced, whereas the activity of CAT and ascorbate (APX) increased. Therefore, according to these results, VdGATA2 benefitted transgenic Arabidopsis plants in two ways: by preventing oxidative damage and enhancing their resistance to powdery mildew.