The rolB gene prevents cell death induced by paraquat. A, Phenotypes of the cultures; B, cell count. The control cells (R line), high-rolB-expressing cells (RB-H line), and high-rolC-expressing cells (RC-H line) were cultivated in the presence of 100 μm paraquat for 8 d in the dark or in the light (200 μmol m−2 s−1 radiation). Then, the cells were stained with propidium iodide and analyzed by confocal microscopy. Forty to 50 cells were counted in each variant, and the percentage of nonviable cells was calculated. The data are presented as mean ± se from a single experiment with three replicates.