ANALYSIS OF THE PETUNIA NITRATE REDUCTASE APOENZYME-ENCODING GENE - A1ST STEP FOR SEQUENCE MODIFICATION ANALYSIS

In this paper, we describe the gene (nia) coding for the apoenzyme of the nitrate reductase (NR) of petunia. A full-size genomic clone was i solated from a genomic library, using the tobacco nia2 cDNA as a probe , and sequenced. The open reading frame is interrupted by three intron s and encodes a protein of 909 amino acids which reveals between 92% a nd 68% identity to the NADH NR apoenzyme from other higher plants. Sou thern analyses indicated that the NR apoenzyme is encoded by a single- copy gene, although another region homologous to part of nia was also identified. The analysis of the steady-state level of nia mRNA showed that the petunia nia is regulated by the nitrogen source and is under the control of the circadian rhythm.