Figure 4.

Truncation of MED8 Q-rich domain confers tolerance to MV. A, Phenotypes of 3-week-old Col-0, med8, and MED8 overexpression lines (MED8OE-1/2/3). Plants were grown on ½ MS medium with or without 25 nM, in a long-day photoperiod (16-h light/8-h dark) and under a light intensity of 80 μmol·m⁻²·s⁻¹. B, Rosette area quantification of med8 and MED8OE lines grown in the same condition as in (A). The data are means ± SE of 16 biological replicates. The different letters indicate statistically significant difference between Col-0, med8, and MED8OE lines under control conditions analyzed with one-way ANOVA followed by Duncan’s test (P ≤0.05). Numbers above the bars indicate the reduction percentage of the rosette areas in the respective genotypes. Asterisks indicate a significant difference in MV resistance between mutant and Col-0 analyzed with two-way ANOVA (P ≤0.05). NS, no significant differences. C, Glutathione content in med8 mutants in response to MV-induced oxidative stress. Glutathione content in 3-week-old Col-0 and med8 plants grown on ½ MS medium with or without 25-nM MV. White and black bars indicate GSH and glutathione disulfide (GSSG) content, respectively. Numbers above the bars indicate glutathione reduction states in Col-0 and med8 plants under control conditions and MV stress. The data are means ± se of biological triplicates. Asterisk indicates a significant difference at P ≤ 0.05 (Student’s t test) between Col-0 and the med8 mutant. D, MED8 transcript levels, relative to ARP7 and UBIQUITIN, in the respective overexpression lines. The data are means ± SE of three biological replicates. E, Fresh weight of 3-week-old Col-0, med8, and MED8OE plants grown on ½ MS medium. The data are means ± SE of eight biological replicates. The different letters indicate statistically significant difference analyzed with one-way ANOVA followed by Duncan’s test (P ≤ 0.05). F, Phenotypes of 3-week-old plants grown in soil at an irradiance of 100 µmol·m⁻²·s⁻¹ in long days (16-h light/8-h dark).