Figure 2.

H₂O₂ production induced by Vd-toxins in the leaves of wild-type Arabidopsis Columbia-0 (Col-0) and mutants. A, H₂O₂ was detected by fluorescence resulting from H₂DCF-DA, as described in “Materials and Methods.” Bar = 100 μm. B, Quantification of the H₂DCF-DA fluorescence intensities in A. Error bars indicate sd; n = 8. Different letters represent significant differences at P < 0.05 by one-way ANOVA with Tukey’s honestly significant difference posthoc tests. C, Quantitative measurements of H₂O₂ concentrations in the leaves using the chromogenic peroxidase-coupled assay. Error bars indicate sd; n = 3. D, Relative expression levels of GST1 after treatment with 150 μg mL⁻¹ Vd-toxins in the wild type, the hub1-4, hub2-2, and hub1-4 hub2-2 mutants, and the HUB1/hub1-4 complementation line. Seedlings treated with double distilled water were used as controls. Total RNA was extracted 24 h after the Vd-toxins treatment for RT-qPCR analysis. Error bars indicate sd; n = 3. All experiments were repeated at least three times.