FIG. 6.

HRL1 overexpression makes plants less sensitive to reactive oxygen species (ROS). (A) Seedlings of HRL1 overexpression lines and wild-type Col-0 were grown in normal Peters media (JR PETERS, Inc., Allentown, PA) under a 16 h light/8 h dark cycle for 14 days. Response to a high ROS environment was analyzed by transferring these seedlings to either a 23 h light/1 h dark cycle or Peters media with 150 mM NaCl or Peter's media with 1 μM paraquat. Seedlings were photographed after 1 week of exposure to a high ROS environment. The entire experiment was repeated at least twice more with plants grown at different times, and similar results were obtained. (B) Staining for hydrogen peroxide (DAB staining) and superoxide (NBT staining) levels in Col-0 and HRL1 overexpression lines under different nonbiotic stresses. Seedlings were harvested for staining after 48 h of high ROS environment. The entire experiment was repeated at least twice more, and plants grown at different times and similar results were obtained. (C) Gene expression analysis of AtrbohF and Aox1d by real-time PCR in Col-0 and HRL1 overexpression lines under different abiotic stresses. Seedlings were harvested for RNA isolation after 48 h of high ROS environment. The entire experiment was repeated at least twice more with plants grown at different times, and similar results were obtained. Asterisks indicate statistically significant differences (*p<0.001, Mann–Whitney test). To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars