Abstract: Total RNAs were extracted from the petals of Petunia hybrida strains with different flower colors. Using Olig (dT) as pimer, the total RNAs were synthesized into the first strand of cDNA by reverse transcription reaction. By Polymerase Chain Reaction (PCR)amplificaton, we obtained a cDNA fragdesigned according to the cDNA encoding region of cytochrome b5 protein that were reported previously. The PCR products were cloned into pGEM-T vector,respectively. We analyzed the sequences of different recombinant plasmids and compared them with the reported cDNA sequence of Cyt b5. We found that their encoding areas all contain 447 nucleotides and encode 149 amino acid residues. However, the cDNAs from violet and blue Petunia have one different nucleotide, but without different amino acid residues from the reported cDNA; those from pink and white Petunia have three different nucleotides and two different amino acid residues from the reported cDNA. These results imply that the Cyt b5 gene regulation on flower color may be relevant to the primary structure of its encoding cDNA.

Key words: Flower color