Figure 4.

Salt stress induces OsHKT1;1 promoter activity. A, The schematic diagram shows the constructs of 5′ terminal deletion mutants of the OsHKT1;1 promoter that are linked with the reporter gene GUS. B, GUS image of N. benthamiana leaves. The N. benthamiana leaves were infiltrated with agrobacterial stains containing constructs with different promoters indicated under the images at right. These leaves were separated into left and right parts as indicated in the image at left. The left part of each leaf was treated with 100 mm NaCl, and the right part was immersed in blank solution for 2 h. The treated leaves were stained with 5-bromo-4-chloro-3-indolyl-β-glucuronic acid and cleared with ethanol. Representative images are shown. C, GUS activity assay of the N. benthamiana leaves indicated in B. Asterisks indicate that the mean value is significantly different from that of the control: *, P < 0.05. Error bars represent se (n = 3). 4-MU, 4-Methylumbelliferone.