Figure 5

Gene transfer of sdh3 . A. Schematic diagram of sdh3 gene transfer from mitochondrial genome to the nucleus. A transposable element (TE) insertion is shown in red in the mitochondrial DNA. The dashed line outlines a pseudogene due to mutations in the start codon as indicated. Boxes and oval indicate mitochondrial targeting presequence (mTP; blue), heat shock protein (hsp; orange), and a conserved domain (succinate dehydrogenase C; red). B. Nucleotide sequence alignment of the nuclear, transcript, and mitochondrial copies of Rhazya stricta. The shaded red area shows the intron within predicted heat shock protein (hsp22). C. Amino acid sequence alignment of Rhazya nuclear and mitochondrial sdh3 with six nuclear-encoded and three mitochondrial-encoded copies from other angiosperms (see Additional file 1: Table S13). Boxes indicate mitochondrial targeting presequence (blue) and a conserved domain of succinate dehydrogenase C (red), and shaded red boxes indicate the remaining portions of genes into which sdh3 was transferred (heat shock proteins, Rhazya and Gossypium-hsp22, Arabidopsis-hsp70; Iron-sulfur cluster scaffold-like protein, Ledum; hypervariable Bacillus group-specific protein, Strychnos; Pyrimidine (PYR) binding domain of thiamine pyrophosphate (TPP)-dependent enzyme, Lobelia). mt = mitochondrial, n = nuclear.