Characterization of the complete chloroplast genome of the endangered <Emphasis Type="Italic">Przewalskia tangutica</Emphasis> Maxim

Przewalskia tangutica Maxim., an endangered medicinal species, is endemic to the Qinghai-Tibetan Plateau of China. In this study, we sequenced and characterized the chloroplast genome of P. tangutica for the first time. The P. tangutica chloroplast genome is 155,569 bp in length, exhibits a typical quadripartite structural organization, consisting of a LSC region of 86,707 bp, two IR regions of 25,287 bp and a SSC region of 18,288 bp. The genome contains 138 complete genes, including 85 protein-coding genes (85 PCG species), 44 tRNA genes (21 tRNA species) and eight rRNA genes (four rRNA species, rrn16S, rrn23S, rrn4.5 S, rrn5S). The most of gene species occur as a single copy, while 18 gene species occur in double copies including eight PCG species, six tRNA species (trnN, trnR, trnA, trnI, trnV, trnL) and all of rRNA species. Further, phylogenetic analysis indicated that P. tangutica clustered together with Scopolia parviflora, and formed a clade with Hyoscyamus niger in the Solanaceae. The whole chloroplast genome of P. tangutica not only provides important insight into conservation and restoration efforts for P. tangutica, but also plays a critical role in phylogenetic and evolution studies of the Solanaceae family. More importantly, it will contribute to the ongoing efforts for maintenance of existing genetic resource in the Qinghai-Tibet Plateau.