The wheat mitochondrial rps13 gene: RNA editing and co-transcription with the atp6 gene

Northern analyses and reverse transcription-polymerase chain-reaction (RT-PCR) experiments, followed by PCR amplification product sequencing, were performed on total mitochondrial (mt) RNAs from wheat seedlings and tissue cultures. It was shown that the rps13 gene, which encodes ribosomal protein S13, and the atp6 gene, which encodes subunit 6 of the ATP synthase complex, were co-transcribed. However, rps13 transcripts were virtually undetectable in seedlings under conditions where atp6 transcripts appeared abundant. In addition, markedly higher steady state transcript levels were observed in tissue culture. Expression of the mitochondrial rps13 gene was confirmed by showing that its transcripts were edited. Slight differences between editing patterns of tissue-culture and whole-plant transcripts were found. Taken together, these results suggest that in vitro culture could disturb the post-transcriptional regulation of gene expression.