Abstract
RNA editing is a maturation process where the insertion, deletion or substitution of nucleotides occurs in transcripts. For chloroplast transcripts in land plants, specific C-residues are edited to U-residues, resulting mostly in restoring the conserved amino acid residues. Previous studies showed that RNA editing varies in the efficiency at different tissues and/or developmental stages. In this study, the possibility that editing efficiency in tobacco chloroplasts changes with light/dark conditions is inquired. We previously identified all the 38 sites in transcripts of tobacco chloroplasts. Comparison in editing efficiency at the respective sites between young leaves in light and seedlings in darkness revealed that at the four editing sites of three genes (rpoA, ndhA and ndhD), the efficiency in C-to-U substitution alters significantly depending on the presence or absence of light. Clearly, RNA editing is involved in light regulation of expression of the above three genes in the chloroplast genome of tobacco.
