To elucidate the evolution of mitochondrial genomic diversity within a single order of angiosperms, we sequenced seven Brassicales genomes and the transcriptome of Brassica oleracea. In the common ancestor of Brassicaceae, several genes of known function were lost and the ccmFN gene was split into two independent genes, which also coincides with a trend of genome reduction towards the smallest sequenced angiosperm genomes of Brassica. For most ORFs of unknown function, the lack of conservation throughout Brassicales and the generally low expression and absence of RNA editing in B. oleracea argue against functionality. However, two chimeric ORFs were expressed and edited in B. oleracea, suggesting a potential role in cytoplasmic male sterility in certain nuclear backgrounds. These results demonstrate how frequent shifts in size, structure, and content of plant mitochondrial genomes can occur over short evolutionary time scales. oleracea have characteristics of cytoplasmic male-sterility factors.
Bibliographical notePublisher Copyright:
© 2014 Elsevier B.V. and Mitochondria Research Society.
- Genome evolution
- Plant mitochondria
- RNA editing