Fig. 5.

Effect of knocking down and overexpressing GRXS13.2 on the tolerance to methyl viologen (MeV) treatment. (A) Silencing of the GRXS13 gene reduced the ability of Arabidopsis plants to survive in the presence of MeV. Seeds from WT (white bars), Sil lines (grey bars), and OE lines (black bars) were germinated on MS medium alone (C) or supplemented with 0.25 μM MeV (T) under controlled conditions (16 h light, 100 μmol m⁻² s⁻¹, 22±2 °C). At day 4, seedlings were scored for survival rates (percentage of green seedlings with respect to the total germinated seedlings); these scores were compared with the corresponding values of untreated WT seedlings (100%). Data represent mean values ±SD from six biological replicas. (B and C) Overexpressing GRXS13.2 reduces necrotic symptoms after MeV treatment. Analysis of necrotic symptoms that developed in leaves of 5-week-old plants of WT (white bars), Sil lines (grey bars), and OE lines (black bars) after 2 d of MeV treatment (a 2 μl drop of a 15 μM MeV solution). Representative examples of symptoms which developed after MeV treatments are shown in (B). According to the extension of the leaf necrotic area, lesions were scored in a three-point scale I, II, and III, as described in the Materials and methods. (C) The percentage of leaves showing each of the symptoms at day 2 after MeV treatment was scored. Statistical analyses were performed using two-way ANOVA with Bonferroni post-test with the GraphPad Prism 5 program. Values that show statistically significant differences relative to the corresponding WT samples are indicated by an asterisk (P < 0.05).