Figure 8.

Expression of genes encoding nitrate transporters and nitrate reductase. Transcript levels for genes encoding nitrate transporters (NRT1.1 and NRT2.1) and nitrate reductase (NIA1 and NIA2) were determined by qRT-PCR in the roots of 15-d-old seedlings grown under axenic conditions on 3 mm KNO₃. Expression in mutant SDH1-1/sdh1-1 seedlings (black bars) is given relative to wild-type seedlings (gray bars; set to 1). Values were normalized using clathrin as an internal control and are shown as means ± se from six biological replicates. Asterisks indicate values that were determined by t test to be significantly different from the wild type (*** P < 0.01).