Vincetoxicum mongolicum Maxim. ( 1876), is a perennial medicinal herb, widely distributed in the Loess Plateau of China. Here, we sequenced, assembled, and annotated the complete chloroplast (cp) genome of V. mongolicum, and compared the highly variable gene regions and phylogenetic positions between V. mongolicum and other related species. Results showed that the complete cp genome of V. mongolicum was 160,157 bp in length, containing a large single copy (LSC) region of 91,263 bp, a pair of inverted repeats (IR) region of 23,892 bp, and a small single copy (SSC) region of 21,110 bp. The GC content accounts for 37.8%, and we annotated 131 single genes, which include 86 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. By comparing and analyzing the variable region of the cp gene of V. mongolicum and other Vincetoxicum, we found that the variable sequences of rpoC1-rpoB, ycf4-cemA, ndhF, ndhF-rpl32, and rpl32-ccsA fragments were highly significant, which could be targeted as the DNA barcodes for evidence of V. mongolicum and its relatives in Apocynaceae. Maximum-likelihood (ML) phylogenetic tree analysis elucidated that V. mongolicum was sister to V. pycnostelma with strong support. Our results provide useful information for future phylogenetic studies and plastid super-barcodes of the family Apocynaceae.

Astragalus melilotoides Pall. 1776 is a perennial leguminous forage, widely distributed in northern China, with cold, drought and disease resistance characteristics. Here, we determined the complete chloroplast (cp) genome sequence of A. melilotoides. It was 123,827 bp in length and 36.97% GC content with IR loss. The cp genome contained 110 complete genes, including 76 protein-coding genes, 30 tRNA genes, and four rRNA genes. A maximum likelihood (ML) phylogenetic tree revealed that A. melilotoides was related to A. americanus , A. gummifer , A. mongholicus , A. nakaianus , A. mongholicus var. nakaianus , and A. membranaceus var. membranaceus . The cp genome analysis of A. melilotoides will provide a reference for the phylogenetic study of Astragalus in the future.

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