Organ-Specific Expression of Plastid-Encoded Genes in Rice Involves both Quantitative and Qualitative Changes in mRNAs

The steady-state transcript levels for psbA, psbC, psaA and rbcL in rice are substantially low (less than 10%) in roots than in aerial parts. However, psbB-specific transcripts show comparatively higher (about 40%) accumulation even in roots. These results have been discussed in relation to gene dosage. The number of transcripts for psbB and psbC is lower in roots than the aerial parts. In addition, a novel transcript appears in roots for psbB reflecting on the existence of mechanism(s) for qualitative differences.