Figure 9.

Inhibition of Mitochondrial Complex III Phenocopies the C17-Tolerance Phenotype of cwm1 and cwm2 Mutants.

(A) Root elongation of wild-type control-treated (DMSO), 1 µM AA-treated, and 50 µM RO-treated plants. Three-day-old seedlings grown on half-strength MS medium were transferred to medium without (left panel) or with (right panel) 200 nM C17 for 2 d. Arrowheads indicate the root tip position at the moment of transfer. Bars = 5 mm.

(B) Quantification of the root elongation of plants after transfer. Data represent mean ± sd (n > 10). Statistically significant differences compared with wild-type plants in the absence of mitochondrial inhibitors are indicated; *P value < 0.01 (two-tailed Student’s t test).

(C) Representative confocal microscopy images of 4-d-old wild type (Col-0) control-treated with 0.1% DMSO (mock) or with 1 µM AA, 200 nM C17 (C17), or a combination of 1 µM AA with 200 nM C17 (C17+AA). Two-hour treated roots were stained with PI. The brittle cell wall was visualized by the uptake of PI. Bar = 100 µm.

(D) to (F) Representative spinning confocal microscopy images of 4-d-old GFP-CESA3 plants treated with 0.1% DMSO (D), 200 nM C17 (E), or a combination of 1 µM AA with 200 nM C17 (F). The images were taken at 20 min after treatment. Bars = 5 µm.

(G) Quantification of fluorescence in (D) to (F). The relative intensity is calculated by the fluorescence per unit area in the root elongation zone of each sample divided by that of the mock-treated plants. Data represent mean ± sd (n = 5). Statistically significant differences compared with wild-type plants in mock are indicated; *P value < 0.01 (two-tailed Student’s t test).