Fig. 5.

The first ATG context is highly conserved in angiosperms. In Lon1-like genes of Sapindales and Brassicales, the chloroplast transit peptide was retained for dual-targeting with twin pre-sequences through ORF preservation (highlighted in blue). In the Lon genes with an ambiguous pre-sequence for dual-targeting, the accumulation of mutational modifications led to deterioration of the chloroplast transit peptide (highlighted in red). The mutations that result in a stop codon are displayed in black underlined bold triplets, whereas the nucleotides that modify the translation initiation codon or shift the reading frame are marked in bold red.