Transcriptional control of the inducible nitrate reductase isoform from soybeans.

The activity of the pH 7.5 NADH-linked nitrate reductase isoform from soybean seedlings is termed inducible. Activity is present only in the leaves of seedlings which have been supplied nitrate. A cDNA clone that encoded part of the mRNA for squash nitrate reductase hybridized specifically with mRNA for this inducible nitrate reductase isoform. Nitrate induction resulted in an increase in the steady-state levels of mRNA for this isoform after 24 hours, while the addition of glutamine to the nitrate diminished steady-steady state levels of this mRNA.