Transcription of the wheat chloroplast gene that encodes the 32 kd polypeptide.

We have mapped and cloned the wheat chloroplast gene (psbA) that encodes the 32 kd polypeptide of Photosystem II. The psbA gene is located in the large single copy region adjacent to one inverted repeat and is transcribed toward the latter. The sequence of the 5' end of the wheat gene is homologous with dicot psbA genes. We have located the 5' terminus of the wheat psbA RNA to a position 83 nt upstream of its coding region. The same psbA RNA species was capped in vitro by guanylyltransferase, establishing that its 5' end is a transcription start site. Regions which resemble procaryotic -10 and -35 promoter elements are located immediately upstream of the wheat psbA transcription initiation site.