A novel soybean mitochondrial transcript resulting from a DNA rearrangement involving the 5S rRNA gene.

A tissue culture line of soybean cells (SB-1) is shown to have an unusual arrangement of mitochondrial genes. Fusion of the mitochondrial 5S gene to the distal end of an unidentified gene results in the abundant expression of an 800 nucleotide RNA with the 5S rRNA at its 5' end. Since only the fused 5S rRNA gene is found in this cell line, the functional 5S rRNA must arise by processing of the 800 nucleotide RNA or by intermittent termination of transcription. The 800 nucleotide transcript and its DNA arrangement are not detected at comparable levels in other soybean sources, including the parent plant of the SB-1 tissue culture line. The role of recombination in the origin of this gene fusion and in plant mitochondrial DNA in general is discussed.