“…Indeed, translational regulation is a major determinant of gene expression in plastids [ 21 , 22 , 23 , 24 ]. The intrinsic mRNA features that determine the efficiency of start codon recognition in plastids of higher plants, and hence, the efficiency of translation initiation, are well characterized: (a) Shine-Dalgarno sequences hybridize to the anti-Shine-Dalgarno sequence at the tail of the 16S rRNA and thereby position the start codon so that it can bind to the initiator tRNA; (b) local minima of mRNA secondary structure around the start codon make it accessible for the ribosome, whereas other AUGs are masked by folded RNA [ 6 , 8 , 25 , 26 , 27 , 28 ].…”