Sugarbeet mitochondria contain an open reading frame showing extensive sequence homology to the subunit 2 gene of the NADH: ubiquinone reductase complex.

Sequence analysis of a transcribed region of mitochondrial DNA (mtDNA) from male fertile sugarbeet (Beta vulgaris L.) revealed an open reading frame showing extensive sequence homology to the subunit 2 gene of the NADH: ubiquinone reductase complex (nad2). Sugarbeet nad2 in common with its proposed counterpart in animal mitochondria has no intron and thereby differs from the corresponding chloroplast gene. Northern RNA analysis of sugarbeet nad2 suggested that transcription of this locus gives rise to at least three transcripts. No differences in transcript profile were detected between male fertile and cytoplasmic male sterile sugarbeet. This constitutes the first report of a mitochondrial nad2 gene in higher plants.