Molecular Organization of the Chloroplast Genome and Taxonomic Position of Stellaria dichotoma var. lanceolate

Stellaria dichotoma L. var. lanceolata Bunge is a typical rare medicinal plant commonly used in therapeutic formulations. To reveal the structural arrangements and variation of complete chloroplast genomes between S. dichotoma var. lanceolata and its related species is of great significance for the study of its evolutionary status. In this study, evolutionary relationships between S. dichotoma var. lanceolata and its related species of Caryophyllaceae were documented based on the complete chloroplast genome sequence of S. dichotoma var. lanceolata. The result showed that the whole circular genome of S. dichotoma var. lanceolata was 150 461 bp in length, annotated 129 genes, possessing RSCU of 21 types of amino acids and 64 codons encoding. By comparing and analyzing the SSR and variation region of the chloroplast gene of S. dichotoma var. lanceolata and its related genus pseudostellaria, the authors found that the divergent regions of trnk-rps16, atpH-atpI, rpoC1-rpoB, rbcL-accD, trnS-trnG, psaA-ycf3, trnV-trnM, ycf4-cemA, petL-petG, trnL-ccsA, ndhF, ndhA, and ycf1 fragments were highly obvious, which could be used as DNA barcodes for the taxonomic evidence of S. dichotoma var. Lanceolata and Pseudostellaria in Caryophyllaceae. A maximum likelihood (ML) phylogenetic tree elucidated that S. dichotoma var. lanceolata was closely related to pseudostellaria and cluster into a branch with Cerastium. The results lay a robust foundation for future phylogenetic and evolutionary status of S. dichotoma var. lanceolata and among relatives within Caryophyllaceae.