Assembly and comparative analysis of the complete mitochondrial genome of tea-scented China rose

Plant mitochondrial (mt) genomes enable better understanding of cellular processes and phylogenetic relationships. Tea-scented China rose ‘Hume's Blush Tea-scented China’ is the ancestor of the modern hybrid tea rose and has had an important and lasting influence on the breeding of the modern horticultural rose, but a comprehensive description of its mt genome is not yet available. In this study, mature leaves were used to determine the sequence of the rose mt genome. The mt genome of ‘Hume's Blush Tea-scented China’ is a circular sequence 277 730 bp in length and includes 30 protein-coding genes, 19 tRNA genes, and 3 rRNA genes. We analyzed repeat sequences, codon preferences, and RNA editing processes. In addition, we detected the transfer of 25 chloroplast genes to the mt genome, indicating intracellular genes transferred frequently from chloroplasts to mitochondria in ‘Hume's Blush Tea-scented China’. The phylogenetic analysis of the ‘Hume's Blush Tea-scented China’ mt genome and those of 26 other plant groups reflects its taxonomic status. The Ka/Ks of most genes was less than 1, indicating that most coding genes underwent negative selection, while pi was greater than 0.01, confirming highly diverse genetic variation. This work lays a foundation for future investigation of genetic variation in ‘Hume's Blush Tea-scented China’.