Characterization of a cDNA clone encoding 23 kDa polypeptide of the oxygen-evolving complex of photosystem II in rice.

We isolated a cDNA for a gene that encodes the 23 kDa protein of the oxygen-evolving complex of photosystem II in rice. The amino acid sequence deduced from the cDNA is highly similar (71-60% homology) to those of the analogous genes from wheat, tomato, pea, spinach, tobacco and mustard. The expression of the gene that corresponds to the 23 kDa protein was inducible in green organs of mature and immature leaves, stems and young panicles but not inducible in roots. The high level of the transcripts was detected in both mature leaves and young panicles. The expression of the gene was low in etiolated seedlings, while the transcript of the gene was strongly induced by light, and the level of the expression increased during light irradiation. These observations suggest that the expression of the gene encoding the 23 kDa protein is organ-specific and light-inducible.