The Complete Chloroplast Genomes of Two Lancea Species with Comparative Analysis

The genus Lancea is native to the Qinghai-Tibetan Plateau and consists of two species, Lancea tibetica Hook. f. et Thorns. and Lancea hirsuta Bonati. Here, we report the complete sequences of the chloroplast genomes of L. tibetica and L. hirsuta, which were 153,665 and 154,045 bp in length, respectively, and each included a pair of inverted repeated regions (25,624 and 25,838 bp in length, respectively) that were separated by a large single copy region (84,401 and 84,588 bp in length, respectively) and a smaller single copy region (18,016 and 17,781 bp in length, respectively). A total of 106 genes in L. tibetica and 105 in L. hirsuta comprised 79 protein-coding genes, and 4 ribosomal RNA (rRNA) genes, as well as 23 and 22 transfer RNA (tRNA) genes in L. tibetica and L. hirsuta, respectively. The gene order, content, and orientation of the two Lancea chloroplast genomes exhibited high similarity. A large number of informative repetitive sequences, including SSRs, were observed in both genomes. Comparisons of the genomes with those of three other Lamiales species revealed 12 highly divergent regions in the intergenic spacers and in the matK, rpoA, rps19, ndhF , ccsA, ndhD, and ycf1 coding regions. A phylogenomic analysis suggested that Lancea forms a monophyletic group that is closely related to the Glade composed of the families Phrymaceae, Paulowniaceae, and Rehmanniaceae.