ANALYSIS OF SILENT RNA EDITING SITES IN ATP6 TRANSCRIPTS OF SORGHUM-BICOLOR

We have observed numerous examples of silent or rare non-silent editin g sites in the amino-extension and part of the conserved core of mitoc hondrial atp6 transcripts of Sorghum. In this region of the 1.4-kb atp 6-2 mRNA (position 300 to 550) two editing sites, which alter the amin o-acid sequence and occur in all cDNAs analysed, were already known, w hile nine others were found which are silent or occur in a few mRNAs o nly. Many aspects of RNA editing in the mitochondria of higher plants are still unknown. This includes the influence of genomic background o r silent RNA editing, We were interested in the influence of nuclear a nd mitochondrial backgrounds on RNA editing, Previous preliminary resu lts indicated the possibility of line-specific editing at silent sites . However, a more comprehensive approach gave no consistent evidence f or such editing. These results are discussed with respect to their pot ential impact on the evolution of mitochondrial genes.