Project description:Mirabilis himalaica (Nyctaginaceae) is endemic to the Himalayas where it is used in traditional Tibetan folk medicine. In this study, we first presented the complete chloroplast genome of M. himalaica. Complete genome size of M. himalaica ranged from 154,348 to 154,388 bp. The length varied from 85,808 to 85,845 bp in the (large single-copy) LSC region, from 17,935 to 17,938 bp in the (small single-copy) SSC region, and from 25,302 to 25,303 bp in the inverted repeat (IR) region. The overall GC contents of the chloroplast genome sequences were around 36%. Annotation analysis revealed a total of 112 genes, including 78 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. The phylogenetic analysis with three M. himalaica samples and five other Nyctaginaceae species showed that Mirabilis including two species was clustered with high bootstrap support. The complete chloroplast genome sequences obtained in this study will provide valuable data for wider studies into the phylogenetics and conservation biology of M. himalaica.
Project description:Mirabilis himalaica is an old and popular medicinal plant used in traditional Tibetan folk medicine. Here, we reported the complete chloroplast genome sequence of Mirabilis himalaica. The assembled chloroplast genome was 154,348 bp long, containing a large single-copy region of 85,809 bp, a small single-copy region of 17,935 bp, and a pair of inverted repeat regions of 25,302 bp. It had 36% GC content and encoded 131 genes including 86 protein-coding genes, eight rRNA genes, and 37 tRNA. Fifteen and two genes contained one and two introns, respectively. Phylogenetic analysis revealed that Mirabilis himalaica was sister to Nyctaginia capitata.
Project description:Crucihimalaya himalaica, a close relative of Arabidopsis and Capsella, grows on the Qinghai-Tibet Plateau (QTP) about 4,000 m above sea level and represents an attractive model system for studying speciation and ecological adaptation in extreme environments. We assembled a draft genome sequence of 234.72 Mb encoding 27,019 genes and investigated its origin and adaptive evolutionary mechanisms. Phylogenomic analyses based on 4,586 single-copy genes revealed that C. himalaica is most closely related to Capsella (estimated divergence 8.8 to 12.2 Mya), whereas both species form a sister clade to Arabidopsis thaliana and Arabidopsis lyrata, from which they diverged between 12.7 and 17.2 Mya. LTR retrotransposons in C. himalaica proliferated shortly after the dramatic uplift and climatic change of the Himalayas from the Late Pliocene to Pleistocene. Compared with closely related species, C. himalaica showed significant contraction and pseudogenization in gene families associated with disease resistance and also significant expansion in gene families associated with ubiquitin-mediated proteolysis and DNA repair. We identified hundreds of genes involved in DNA repair, ubiquitin-mediated proteolysis, and reproductive processes with signs of positive selection. Gene families showing dramatic changes in size and genes showing signs of positive selection are likely candidates for C. himalaica's adaptation to intense radiation, low temperature, and pathogen-depauperate environments in the QTP. Loss of function at the S-locus, the reason for the transition to self-fertilization of C. himalaica, might have enabled its QTP occupation. Overall, the genome sequence of C. himalaica provides insights into the mechanisms of plant adaptation to extreme environments.