Fig 1.

The Rf locus contains two tandem mitochondrially targeted PPR motif genes. (A) Genomic organization of the region containing the Rf-PPR592 and Rf-PPR591 genes. Duplicated blocks are indicated by similar colors. Arrows indicate the direction of transcription. 1 and 2 show locations of the primers used to amplify the rf-PPR592 gene from a CMS plant. (B) A single onion epidermal cell expressing a known mitochondrially targeted GFP after DNA bombardment. (C) A single onion epidermal cell transiently expressing 44 N-terminal amino acids of Rf-PPR592 fused to GFP. (D) Comparison of PPR motifs found in Rf-PPR592 with the MEME-derived consensus from 1,303 PPR motifs. The 14 PPR repeats are sorted by decreasing statistical significance, with PPR 230–264 showing the highest match to the consensus motif that is generated by retaining only the amino acids that occur at least in 6 of the 14 repeats. The color code is taken from the MEME output.