The complete plastome genome sequence of Cynanchum otophyllum (Asclepiadaceae), a unique medicinal species in China.

Cynanchum otophyllum Schneid is an important medicinal plant in China. In this paper, the chloroplast genome of C. otophyllum was sequenced based on high-throughput technology, and the chloroplast genome structure characteristics and phylogenetic relationship of C. otophyllum were analyzed. The results showed the complete plastome genome size of C. otophyllumis 160,874bp, including one small single copy (SSC, 19,851bp) and one large single copy (LSC, 92,009bp) regions isolated by a pair of inverted repeat regions (IRs, 24,507bp). The whole plastome genome including 84 protein encoding genes, 8 rRNA and 37 tRNA. Based on the phylogenetic topologies, C. otophyllum shows close association with additional Gomphocarpus and Asclepias genus. This study contributes to an enhanced understanding of the genetic information of C. otophyllum and provides a theoretical basis for the development of molecular markers and phylogeographic of the species, as well as for constructing the phylogenetic tree of Asclepiadaceae.

Cloning and Functional Characterization of NADPH-Cytochrome P450 Reductases in Aconitum vilmorinianum.

Diterpenoid alkaloids (DAs) are major pharmacologically active ingredients of Aconitum vilmorinianum, an important medicinal plant. Cytochrome P450 monooxygenases (P450s) are involved in the DA biosynthetic pathway, and the electron transfer reaction of NADPH-cytochrome P450 reductase (CPR) with P450 is the rate-limiting step of the P450 redox reaction. Here, we identified and characterized two homologs of CPR from Aconitum vilmorinianum. The open reading frames of AvCPR1 and AvCPR2 were found to be 2103 and 2100 bp, encoding 700 and 699 amino acid residues, respectively. Phylogenetic analysis characterized both AvCPR1 and AvCPR2 as class II CPRs. Cytochrome c and ferricyanide could be reduced with the recombinant proteins of AvCPR1 and AvCPR2. Both AvCPR1 and AvCPR2 were expressed in the roots, stems, leaves, and flowers of A. vilmorinianum. The expression levels of AvCPR1 and AvCPR2 were significantly increased in response to methyl jasmonate (MeJA) treatment. The yeasts co-expressing AvCPR1/AvCPR2/SmCPR1 and CYP76AH1 all produced ferruginol, indicating that AvCPR1 and AvCPR2 can transfer electrons to CYP76AH1 in the same manner as SmCPR1. Docking analysis confirmed the experimentally deduced functional activities of AvCPR1 and AvCPR2 for FMN, FAD, and NADPH. The functional characterization of AvCPRs will be helpful in disclosing molecular mechanisms relating to the biosynthesis of diterpene alkaloids in A. vilmorinianum.

Comparative Genomic and Phylogenetic Analysis of Chloroplast Genomes of Hawthorn (Crataegus spp.) in Southwest China.

The hawthorns (Crataegus spp.) are widely distributed and famous for their edible and medicinal values. There are ∼18 species and seven varieties of hawthorn in China distributed throughout the country. We now report the chloroplast genome sequences from C. scabrifolia, C. chungtienensis and C. oresbia, from the southwest of China and compare them with the previously released six species in Crataegus and four species in Rosaceae. The chloroplast genome structure of Crataegus is typical and can be divided into four parts. The genome sizes are between 159,654 and 159,898bp. The three newly sequenced chloroplast genomes encode 132 genes, including 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Comparative analysis of the chloroplast genomes revealed six divergent hotspot regions, including ndhA, rps16-trnQ-UUG, ndhF-rpl32, rps16-psbK, trnR-UCU-atpA and rpl32-trnL-UAG. According to the correlation and co-occurrence analysis of repeats with indels and SNPs, the relationship between them cannot be ignored. The phylogenetic tree constructed based on the complete chloroplast genome and intergenic region sequences indicated that C. scabrifolia has a different origin from C. chungtienensis and C. oresbia. We support the placement of C. hupehensis, C. cuneata, C. scabrifolia in C. subg. Crataegus and C. kansuensis, C. oresbia, C. kansuensis in C. subg. Sanguineae. In addition, based on the morphology, geographic distribution and phylogenetic relationships of C. chungtienensis and C. oresbia, we speculate that these two species may be the same species. In conclusion, this study has enriched the chloroplast genome resources of Crataegus and provided valuable information for the phylogeny and species identification of this genus.

Comparative chloroplast genome analysis of medicinally important Veratrum (Melanthiaceae) in China: Insights into genomic characterization and phylogenetic relationships.

Members of Veratrum are perennial herbs widely used in traditional Chinese medicine to induce vomiting, resolve blood stasis and relieve pain. However, the intrageneric classification and phylogenetic relationships within Veratrum have long been controversial due to the complexity of morphological variations and lack of high-resolution molecular markers. In this study, we reevaluated the infrageneric relationships with the genus Veratrum using complete chloroplast genome sequence data. Herein, the complete cp genomes of ten species of Veratrum were newly sequenced and characterized. The complete cp genomes of ten species of Veratrum had the typical quadripartite structure, ranging from 151,597 bp to 153,711 bp in size and comprising a total of 135 genes. The structure of Veratrum cp genomes (i.e., gene order, content, and genome components) was highly similar across species. The number of simple sequence repeats (SSRs) ranged from 63 to 78, and of long repeats ranged from 31 to 35. Eight highly divergent regions (ndhF, psbC-psbZ, psbK-psbI, rpoB-trnC_GCA, trnK_UUU-trnQ_UUG, trnS_GCU-trnG_UCC, trnT_UGU-trnL_UAA and ycf1) were identified and are potentially useful for the DNA barcoding of Veratrum. Phylogenetic analysis among 29 taxa based on cp genomes, total genes, protein-coding genes and intergenic regions strongly supported the monophyly of Veratrum. The circumscription and relationships of the infrageneric taxa of Veratrum were well-presented with great resolution. These results will facilitate the identification, taxonomy, and utilization of Veratrum plants as well as the evolutionary studies of Melanthiaceae.

Characterization of the complete chloroplast genome sequence of Anisodus acutangulus (Solanaceae).

Anisodus acutangulus is a Solanaceae perennial plant, which is endemic to China and classified as an endangered species. In this study, we have sequenced the complete chloroplast genome of A. acutangulus, which is 156,079 bp in length, containing a large single-copy (LSC) region of 86,526 bp, a small single-copy (SSC) region of 17,741 bp and comprises a pair of inverted repeat regions (IRs) of 25,906 bp. Totally 134 genes were annotated, including 87 protein-coding genes, 39 tRNA genes, and 8 rRNA genes. Its overall GC content is 37.6%. Phylogenetic analysis using total chloroplast genome DNA sequence of 21 species revealed that A. acutangulus was closely related to Hyoscyamus niger with 100% bootstrap value.

The complete plastid genome sequence of Neopicrorhiza scrophulariiflora (Plantaginaceae): an endangered species endemic to The Himalayas regions.

Neopicrorhiza scrophulariiflora (Pennell) Hong, an endangered perennial species, is endemic to the Eastern Himalayas and Hengduan Mountains. In this study, we have sequenced the complete chloroplast genome of N. scrophulariiflora, which is 152,643 bp in length, including two inverted repeat (IR, 25,829 bp) regions, one large single copy region (LSC) and one small single copy region (SSC) of 83,191 bp and 17,794 bp, respectively. The cp genome has 131 annotated genes, including 86 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The overall GC content of it is 38.1%. Phylogenetic analysis using total chloroplast genome DNA sequence of 14 species revealed that N. scrophulariiflora was closely relates to two species of Veronica with 100% bootstrap value.

Complete chloroplast genome sequences of two Amomum species (Zingiberaceae).

Amomum tsao-ko and Amomum paratsaoko are well known medicinal and edible plants with a strong fragrance and flavour in China. Here, we have sequenced the two complete chloroplast genomes of Amomum tsao-ko and Amomum paratsaoko, which are 163,612 bp and 163,487 bp in length, respectively, and exhibited LSC and SSC regions separated by a pair of inverted repeat regions. The cp genome of A. tsao-ko has 120 annotated genes, including 82 protein-coding genes, while A. paratsaoko has 121 annotated genes, including 83 protein-coding genes. Both cp genomes contained 30 tRNA genes and 8 rRNA genes. Phylogenetic analysis using a total chloroplast genome DNA sequence of 28 species revealed a close relationship between A. tsao-ko and A. paratsaoko with 100% bootstrap value.

The complete chloroplast genome sequence of Erigeron breviscapus and Erigeron multiradiatus (Asteraceae).

The complete chloroplast genomes of Erigeron breviscapus (Vant.) Hand-Mazz and Erigeron multiradiatus (Lindl.) Benth were reported in this study. The complete chloroplast genomes were 152,367 bp and 152,281 bp for E. breviscapus and E. multiradiatus, respectively. Erigeron breviscapus including two inverted repeat (IRs, 24,692 bp) regions, one large singe copy region (LSC) and one small singe copy region (SSC) of 84,881 bp and 18,102 bp, whereas E. multiradiatus contained IRs of 24,691 bp, LSC of 84,789 bp and SSC of 18,110 bp. The chloroplast genomes both contained 129 genes, including 84 protein-coding genes, 37 tRNA genes, and 8 rRNA genes.

Complete chloroplast genome sequence of Swertia mileensis (Gentianaceae): a medicinal species endemic to China.

Swertia mileensis is an important medicinal plant endemic to South-east Yunnan, China, which has been widely used to treat icteric hepatitis. The complete chloroplast genome sequence of S. mileensis is presented in this study, the total size is 153,015 bp in length with a typical quadripartite structure including a pair of inverted repeat (IRs, 25,786 bp) regions separated by a large single copy (LSC, 83,048 bp) region and a small single copy (SSC, 18,395 bp) region. The overall GC content of it is 38.2%. The cp genome has 134 annotated genes, including 85 protein-coding genes, 37 tRNA genes and 8 rRNA genes. Among these genes, nine genes have one intron and two genes contain two introns. The phylogenetic tree based on 16 complete plastomes of support close relationships among two species of Swertia with 100% bootstrap value.

The complete chloroplast genome and phylogenetic analysis of Veratrum mengtzeanum Loes. F. (Liliaceae).

Veratrum mengtzeanum Loes. F. is a medicinal plant belonging to the genus Veratrum (Liliaceae). In the present study, we assembled and characterized the complete chloroplast (cp) genome of this species. The chloroplast genome is 152,051 bp in length, with one large single copy (LSC) region and one small single copy (SSC) region of 82,112 bp and 17,544 bp, respectively; two inverted repeat (IR) regions of 26,198 bp. It contains 131 annotated genes, including 85 protein-coding genes (PCGs), 38 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. Phylogenetic analysis indicated that V. mengtzeanum was closely related to Veratrum japonicum with 100% bootstrap value.

The complete chloroplast genome sequence of Aconitum austroyunnanense W. T. Wang (Ranunculaceae): a medicinal plant endemic to China.

The complete chloroplast (cp) genome of Aconitum austroyunnanense W. T. Wang, a rare and endangered medicinal plant endemic to southwestern China, was sequenced to be 155,818 bp in length, including two inverted repeat (IR, 26,128 bp) regions, one large single-copy region (LSC) and one small single-copy region (SSC) of 86,555 bp and 17,007 bp, respectively. The cp genome has 131 annotated genes, including 85 protein-coding genes, 37 tRNA genes, 8 rRNA genes, and a pseudogene (ycf1). The overall GC content of it is 38.1%. Phylogenetic analysis revealed that the cp genome of A. austroyunnanense is closely related to that of Aconitum hemsleyanum.