Plastid gene expression during fruit ripening in tomato.

A tomato chloroplast genome map has been constructed with the restriction enzymes Hpa I, Pvu II, and Sal I. Twelve plastid genes have been located on the tomato plastid genome (159 kb).The expression of plastid genes during tomato fruit ripening has been studied. The levels of transcripts of various genes coding for proteins of the photosystem I (psaA), photosystem II (psbA, psbB, psbC, psbD) and the stroma (rbcL) decrease when plastids differentiate from chloroplasts to chromoplasts. The amount of plastid ribosomal RNA also decreases. Transcripts of the genes for the P700 reaction center protein (psaA), for the photosystem II-associated proteins (psbC, psbD) and for the large subunit of ribulose-1,5-bisphosphate carboxylase (rbcL) cannot be detected in chromoplasts. In contrast, a relatively high level of mRNA is present for the 32 kD protein ('herbicide-binding protein', psbA) in red fruit.