BackgroundEpilithic sister genera Oresitrophe and Mukdenia (Saxifragaceae) have an epilithic habitat (rocky slopes) and a parapatric distribution in East Asia, which makes them an ideal model for a more comprehensive understanding of the demographic and divergence history and the influence of climate changes in East Asia. However, the genetic background and resources for these two genera are scarce.ResultsThe complete chloroplast (cp) genomes of two Oresitrophe rupifraga and one Mukdenia rossii individuals were reconstructed and comparative analyses were conducted to examine the evolutionary pattern of chloroplast genomes in Saxifragaceae. The cp genomes ranged from 156,738 bp to 156,960 bp in length and had a typical quadripartite structure with a conserved genome arrangement. Comparative analysis revealed the intron of rpl2 has been lost in Heuchera parviflora, Tiarella polyphylla, M. rossii and O. rupifraga but presents in the reference genome of Penthorum chinense. Seven cp hotspot regions (trnH-psbA, trnR-atpA, atpI-rps2, rps2-rpoC2, petN-psbM, rps4-trnT and rpl33-rps18) were identified between Oresitrophe and Mukdenia, while four hotspots (trnQ-psbK, trnR-atpA, trnS-psbZ and rpl33-rps18) were identified within Oresitrophe. In addition, 24 polymorphic cpSSR loci were found between Oresitrophe and Mukdenia. Most importantly, we successfully developed 126 intergeneric polymorphic gSSR markers between Oresitrophe and Mukdenia, as well as 452 intrageneric ones within Oresitrophe. Twelve randomly selected intergeneric gSSRs have shown that these two genera exhibit a significant genetic structure.ConclusionsIn this study, we conducted genome skimming for Oresitrophe rupifraga and Mukdenia rossii. Using these data, we were able to not only assemble their complete chloroplast genomes, but also develop abundant genetic resources (cp hotspots, cpSSRs, polymorphic gSSRs). The genomic patterns and genetic resources presented here will contribute to further studies on population genetics, phylogeny and conservation biology in Saxifragaceae.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4633-x) contains supplementary material, which is available to authorized users.

Leontice incerta, which belongs to Berberidaceae, is an endangered species in China. In this study, the chloroplast (cp) genome of L. incerta was assembled using genome skimming sequencing and the phylogeny of Berberidaceae was reconstructed based on whole cp genome. The cp genome of L. incerta is 156,923 bp in length, comprising two copies of IR (26,121 bp) regions separated by the LSC (85,622 bp) and SSC (19,059 bp) regions. The cp genome encodes 112 unique genes, consisting of 78 protein-coding genes, 30 tRNA genes, and four rRNA genes, with 19 duplicated genes in the IR regions. Phylogenetic analysis indicates that L. incerta is sister to Gymnospermium microrrhynchum, subsequently is sister to Nandia domestica.

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