Systematics of Mukdenia and Oresitrophe (Saxifragaceae): Insights from genome skimming data

Oresitrophe and Mukdenia (Saxifragaceae) are epilithic sister genera used in traditional Chinese medicine. However, the taxonomy of Mukdenia, especially of M. acanthifolia, has been controversial. Genome skimming of M. acanthifolia and M. rossii, including three individuals for each species is reported and complete plastomes, partial mitogenomes and ETS/ITS sequences were assembled using these data. Their plastomes ranged from 156,341 bp to 157,018 bp in length and had similar structural characteristics and gene content of other flowering plants. These genomes were typically quadripartite, comprising 113 unique genes (79 protein coding genes, 30 tRNAs and 4 rRNAs). Comparative analysis showed that the plastomes of Mukdenia and Oresitrophe were relatively conservative, reflecting the genome size and structure, gene contents, RNA editing sites and codon usage. Five plastid regions that were hotspots of change (trnH-psbA, psbC-trnS, trnM-atpE, petA-psbJ and ccsA-ndhD) were identified withi...