CPGAVAS2, an integrated plastome sequence annotator and analyzer

The complete chloroplast genome of Loropetalum chinense var. rubrum yieh (Hamamelidaceae)

Loropetalum chinense var. rubrum Yieh (L. chinense) is an evergreen shrub or small tree of Hamamelidaceae. In this study, the chloroplast genome sequence of L. chinense is 159,451 bp in length, consisting of a large single-copy region with 88,166 bp (LSC), a small single-copy region with 18,773 bp (SSC), and two inverted repeat regions with 26,256 bp (IRs). The GC content in the chloroplast genome of L. chinense is 38.0%. The chloroplast genome of L. chinense contained 125 genes, including 84 protein-coding genes, 37 tRNA genes, and 4 rRNA genes. The phylogenetic tree showed that L. chinense was closely related to L. subcordatum.

Characterization and analysis of complete chloroplast genome of Clausena anisum-olens (Blanco) Merrill

In this study, the chloroplast genome (Cp) of Clausena anisum-olens ((Blanco) Merrill) was sequenced by high-throughput sequencing technology. We found that the length of the chloroplast genome of Clausena anisum-olens was 159,753 bp, and the total GC content was 38.7%, including a large single-copy (LSC) region of 87,623 bp, a small single-copy (SSC) region of 17,986 bp, and 27,072 bp pairs of reverse repeats (IRS). The Cp genome encoded 129 genes, containing 86 protein-coding, 37 tRNA, and 6 rRNA genes. Phylogenetic analysis of the genome sequence showed that Clausena anisum-olens was closely related to Micromelum minutum and Glycosmis mauritiana.

The complete chloroplast genome of Prunus clarofolia (Rosaceae), a wild cherry endemic to China

Prunus clarofolia (Schneid.) Yu et Li is a very attractive wild flowering cherry endemic to China. In this study, the complete chloroplast genome of P. clarofolia was assembled. The total length of the chloroplast genome was 157,899 bp, containing a pair of inverted repeat regions of 26,393 bp each, separated by a small single-copy region of 19,142 bp, and a large single-copy region of 85,971 bp. The overall GC content of the chloroplast genome was 36.71%. The genome contained 131 genes, including 85 protein-coding genes, 37 tRNA genes, eight rRNA genes, and one pseudogene. Phylogenetic analysis revealed that P. clarofolia and P. pseudocerasus showed the closest relationship.

Characterization of the complete chloroplast genome of Jatropha curcas var. nigroviensrugosus

As a new variety of Jatropha curcas L., Jatropha curcas var. nigroviensrugosus has high development and utilization values because of its high flowering and fruiting rates and yield. In this study, the complete chloroplast (cp) genome of J. nigroviensrugosus was assembled using Illumina sequencing data. Results revealed that its cp genome is 170,811 bp in length and has 106 unique genes, including 76 protein-coding genes, 26 tRNA genes and 4 rRNA genes. Phylogenetic analysis indicated that J. nigroviensrugosus was closely related to J. curcas.

The complete chloroplast genome of Rhus punjabensis var. sinica

Rhus punjabensis var. sinica belongs to the family Anacardiaceae in the order Sapindales. In this study, we first reported the complete chloroplast genome sequence of R. punjabensis var. sinica. The cp genome was sequenced on Illumina Hiseq 2000 platform. The sequence was found to be 159,617 bp in length with 37.9% GC contents, including a large single-copy region of 87,694 bp, a small single-copy region of 18,971 bp, and a pair of inverted repeats of 26,476 bp. The chloroplast genome of R. punjabensis var. sinica contains 133 genes, including 86 protein-coding genes, 8 rRNA genes, and 2 pseudogenes identified by CPGAVAS2 and BLAST search, and 37 tRNA genes annotated by tRNAscan-SE. Maximum-likelihood (ML) phylogenetic analysis showed that R. punjabensis var. sinica was sister to Rhus potaninii.

Complete chloroplast genome of Baccaurea ramiflora and its phylogenetic analysis

Baccaurea ramiflora Lour. is a popular tropical fruit tree, mainly grown in Myanmar, India, and other tropical or sub-tropical regions where it is commonly referred to as Myanmar grapes, Burmese grapes, or Latkan, respectively. Besides food, B. ramiflora is a traditional medicinal plant with several pharmaceutical effects. It is also a crucial component of Chinese Dai medicine. Here, the chloroplast genome of B. ramiflora was sequenced, assembled, and annotated. The complete chloroplast genome is 161,093 bp in length with a GC content of 36.71%. Additionally, it comprises a large single-copy region (LSC) of 89,503 bp, a small single-copy region (SSC) of 18,818 bp, and two inverted repeat regions (IRa and IRb) of 26,386 bp. In total, 128 genes were annotated, including 82 protein-coding genes, 37 tRNA genes, 8 rRNA genes, and 1 pseudogene. Phylogenetic analysis revealed that B. ramiflora is closely related to Phyllanthus emblica, Glochidion chodoense, and Phyllanthus amarus. This study provides useful genomic information for future phylogenetic studies of B. ramiflora and Phyllanthaceae family.

Comparative chloroplast genome analyses of Paraboea (Gesneriaceae): Insights into adaptive evolution and phylogenetic analysis

Paraboea (Gesneriaceae) distributed in the karst areas of South and Southwest China and Southeast Asia, is an ideal genus to study the phylogeny and adaptive evolution of karst plants. In this study, the complete chloroplast genomes of twelve Paraboea species were sequenced and analyzed. Twelve chloroplast genomes ranged in size from 153166 to 154245 bp. Each chloroplast genome had a typical quartile structure, and relatively conserved type and number of gene components, including 131 genes which are composed of 87 protein coding genes, 36 transfer RNAs and 8 ribosomal RNAs. A total of 600 simple sequence repeats and 389 non-overlapped sequence repeats were obtained from the twelve Paraboea chloroplast genomes. We found ten divergent regions (trnH-GUG-psbA, trnM-CAU, trnC-GCA, atpF-atpH, ycf1, trnK-UUU-rps16, rps15, petL, trnS-GCU-trnR-UCU and psaJ-rpl33) among the 12 Paraboea species to be potential molecular markers. In the phylogenetic tree of 31 Gesneriaceae plants including twelve Paraboea species, all Paraboea species clustered in a clade and confirmed the monophyly of Paraboea. Nine genes with positive selection sites were detected, most of which were related to photosynthesis and protein synthesis, and might played crucial roles in the adaptability of Paraboea to diverse karst environments. These findings are valuable for further study of the phylogeny and karst adaptability of Gesneriaceae plants.

Comparative Analysis of Chloroplast Genome and New Insights Into Phylogenetic Relationships of Polygonatum and Tribe Polygonateae

Members of Polygonatum are perennial herbs that have been widely used in traditional Chinese medicine to invigorate Qi, moisten the lung, and benefit the kidney and spleen among patients. However, the phylogenetic relationships and intrageneric taxonomy within Polygonatum have long been controversial because of the complexity of their morphological variations and lack of high-resolution molecular markers. The chloroplast (cp) genome is an optimal model for deciphering phylogenetic relationships in related families. In the present study, the complete cp genome of 26 species of Trib. Polygonateae were de novo assembled and characterized; all species exhibited a conserved quadripartite structure, that is, two inverted repeats (IR) containing most of the ribosomal RNA genes, and two unique regions, large single sequence (LSC) and small single sequence (SSC). A total of 8 highly variable regions (rps16-trnQ-UUG, trnS-GCU-trnG-UCC, rpl32-trnL-UAG, matK-rps16, petA-psbJ, trnT-UGU-trnL-UAA, accD-psaI, and trnC-GCA-petN) that might be useful as potential molecular markers for identifying Polygonatum species were identified. The molecular clock analysis results showed that the divergence time of Polygonatum might occur at ∼14.71 Ma, and the verticillate leaf might be the ancestral state of this genus. Moreover, phylogenetic analysis based on 88 cp genomes strongly supported the monophyly of Polygonatum. The phylogenetic analysis also suggested that Heteropolygonatum may be the sister group of the Polygonatum, but the Disporopsis, Maianthemum, and Disporum may have diverged earlier. This study provides valuable information for further species identification, evolution, and phylogenetic research of Polygonatum.

Complete chloroplast genome of the rare medicinal vegetable Allium hookeri

Allium hookeri is a rare medicinal plant with unique flavor. In this study, the first complete chloroplast (cp) genome of A. hookeri was sequenced and assembled based on the next generation sequencing. The cp genome is 153,592 bp in length, including a large single-copy (LSC) region of 82,609 bp, a small single-copy (SSC) region of 17,487 bp, and a pair of inverted repeat (IR) regions of 26,748 bp each. The genome encodes 131 genes, including 86 protein-coding genes, 39 tRNA genes, and six rRNA genes. The GC content of whole genome is 36.99%. The phylogenetic analysis based on 24 complete cp sequences revealed that A. hookeri was at the base of the phylogenetic tree, indicating an older species in the Allium genus.

Complete chloroplast genome of a cultivated oil camellia species, Camellia gigantocarpa

Camellia gigantocarpa Hu et T. C. Huang, belonging to the Theaceae family, is an excellent landscape tree species with high ornamental value. It is also an important woody oil-bearing plant with high economic value. This study reports the first complete chloroplast genome sequence of C. gigantocarpa (GenBank accession number: MZ054232). Its whole chloroplast genome is 156,953 bp long with an overall GC content of 37.31%, which is composed of a large single copy region (86,631 bp), a small single copy region (18,402 bp), and a pair of inverted repeat regions (25,960 bp each). A total of 135 genes were predicted in this genome, namely eight ribosomal RNA genes, 37 transfer RNA genes, and 90 protein-coding genes. Based on maximum likelihood analysis results, we found that the Camellia species are clustered into a distinct branch, and the phylogenetic relationships among C. gigantocarpa, C. crapnelliana, and C. kissii were the closest.

Complete chloroplast genome of Stephania tetrandra (Menispermaceae) from Zhejiang Province: insights into molecular structures, comparative genome analysis, mutational hotspots and phylogenetic relationships

BACKGROUND

The Stephania tetrandra S. Moore (S. tetrandra) is a medicinal plant belonging to the family Menispermaceae that has high medicinal value and is well worth doing further exploration. The wild resources of S. tetrandra were widely distributed in tropical and subtropical regions of China, generating potential genetic diversity and unique population structures. The geographical origin of S. tetrandra is an important factor influencing its quality and price in the market. In addition, the species relationship within Stephania genus still remains uncertain due to high morphological similarity and low support values of molecular analysis approach. The complete chloroplast (cp) genome data has become a promising strategy to determine geographical origin and understand species evolution for closely related plant species. Herein, we sequenced the complete cp genome of S. tetrandra from Zhejiang Province and conducted a comparative analysis within Stephania plants to reveal the structural variations, informative markers and phylogenetic relationship of Stephania species.

RESULTS

The cp genome of S. tetrandra voucher ZJ was 157,725 bp, consisting of a large single copy region (89,468 bp), a small single copy region (19,685 bp) and a pair of inverted repeat regions (24,286 bp each). A total of 134 genes were identified in the cp genome of S. tetrandra, including 87 protein-coding genes, 8 rRNA genes, 37 tRNA genes and 2 pseudogene copies (ycf1 and rps19). The gene order and GC content were highly consistent in the Stephania species according to the comparative analysis results, with the highest RSCU value in arginine (1.79) and lowest RSCU value in serine of S. tetrandra, respectively. A total of 90 SSRs have been identified in the cp genome of S. tetrandra, where repeats that consisting of A or T bases were much higher than that of G or C bases. In addition, 92 potential RNA editing sites were identified in 25 protein-coding genes, with the most predicted RNA editing sites in ndhB gene. The variations on length and expansion extent to the junction of ycf1 gene were observed between S. tetrandra vouchers from different regions, indicating potential markers for further geographical origin discrimination. Moreover, the values of transition to transversion ratio (Ts/Tv) in the Stephania species were significantly higher than 1 using Pericampylus glaucus as reference. Comparative analysis of the Stephania cp genomes revealed 5 highly variable regions, including 3 intergenic regions (trnH-psbA, trnD-trnY, trnP) and two protein coding genes (rps16 and ndhA). The identified mutational hotspots of Stephania plants exhibited multiple SNP sites and Gaps, as well as different Ka/Ks ratio values. In addition, five pairs of specific primers targeting the divergence regions were accordingly designed, which could be utilized as potential molecular markers for species identification, population genetic and phylogenetic analysis in Stephania species. Phylogenetic tree analysis based on the conserved chloroplast protein coding genes indicated a sister relationship between S. tetrandra and the monophyletic group of S. japonica and S. kwangsiensis with high support values, suggesting a close genetic relationship within Stephania plants. However, two S. tetrandra vouches from different regions failed to cluster into one clade, confirming the occurrences of genetic diversities and requiring further investigation for geographical tracing strategy.

CONCLUSIONS

Overall, we provided comprehensive and detailed information on the complete chloroplast genome and identified nucleotide diversity hotspots of Stephania species. The obtained genetic resource of S. tetrandra from Zhejiang Province would facilitate future studies in DNA barcode, species discrimination, the intraspecific and interspecific variability and the phylogenetic relationships of Stephania plants.

Characterization of the complete chloroplast genome of Rhododendron henanense subsp. lingbaoense Fang

Rhododendron henanense subsp. lingbaoense is endemic in China. The cpDNA of R. henanense subsp. lingbaoense is a typical quadripartite structure with a length of 208,015 bp, including a large single-copy region of 110,593 bp and a small single-copy region of 2606 bp separated by a pair of identical inverted repeat regions of 47,408 bp each. The chloroplast genome contains 119 genes, including 86 protein-coding genes, four ribosomal RNA genes, and 29 transfer RNA genes. The phylogenetic analysis of R. henanense subsp. lingbaoense showed a relatively close relationship with Rhododendron delavayi.

Complete chloroplast genome sequence and phylogenetic analysis of Ilex pernyi Franch

Ilex pernyi Franch. is a Chinese unique medicinal plant with high value for decoration, human consumption, and as a medicine. In this study, we sequenced the complete chloroplast (cp) genome of I. pernyi Franch. and established its phylogenetic relationship in the Aquifoliaceae family. The total length of the chloroplast genome of I. pernyi Franch. was found to be 157,220 bp, with an overall GC content of 37.7% and a typical quadripartite structure with a pair of inverted repeats (IRs, 29,092 bp), which was separated by a small single-copy (SSC) region of 18,427 bp and a large single-copy (LSC) region of 89,609 bp. The cp genome contained 132 genes: 87 protein-coding, 37 tRNA, and 8 rRNA genes. The phylogenetic analysis indicated that I. pernyi Franch. was closely related to Ilex cornuta.

The chloroplast genome of Fallopia aubertii (Polygonaceae) from Xining, China

Fallopia aubertii (L.Henry) Holub (Polygonaceae), a woody plant with a voluble stem, is used as a folk herbal medicines for the treatment of gout, fever and pneumonia. To better understand the molecular genetics of F. aubertii, its complete chloroplast genome was sequenced and annotated. The assembled chloroplast genome is a circular 160,951 bp sequence consisting of large single copy (87,279 bp) and small single copy (13,394 bp) regions, separated by two inverted repeat regions (30,860 bp each). The genome contains 131 genes including 86 protein-coding, 37 tRNA and 8 tRNA genes. Phylogenetic analysis based on the complete chloroplast genome showed that F. aubertii is more closely related to M. australis than to F. sachalinensis, which exhibited a polyphyletic relationship with respect to F. aubertii. These results require further analyses. This study provides additional data for reconstructing species relationships in Fallopia.

Characterization of Pinus densiflora var. zhangwuensis S.J.Zhang, C.X.Li & X.Y.Yuan complete chloroplast genome

Pinus densiflora var. zhangwuensis S.J.Zhang, C.X.Li & X.Y.Yuan, a tree species with promising afforestation potential in northern China. Here, we assembled and annotated the complete chloroplast (cp) genome of P. densiflora var. zhangwuensis using the Oxford Nanopore sequencing technology. The cp genome was 119,725 bp in length, exhibiting a typical quadripartite structure with a large single-copy (LSC: 65,552 bp) and a small single-copy (SSC: 53,183 bp) separated by a pair of inverted repeats regions (IRA and IRB: each of 495 bp) region. The overall GC content is 37.3%. The genome was predicted to encode 112 distinct genes, including 72 protein-coding, 36 tRNA, and four rRNA genes. Maximum-likelihood (ML) phylogenetic for cp genome sequences of 18 Pinaceae species revealed that P. densiflora var. zhangwuensis was closely related to Pinus sylvestris.

Complete Chloroplast Genome Sequence of Erigeron breviscapus and Characterization of Chloroplast Regulatory Elements

Erigeron breviscapus is a famous medicinal plant. However, the limited chloroplast genome information of E. breviscapus, especially for the chloroplast DNA sequence resources, has hindered the study of E. breviscapus chloroplast genome transformation. Here, the complete chloroplast (cp) genome of E. breviscapus was reported. This genome was 152,164bp in length, included 37.2% GC content and was structurally arranged into two 24,699bp inverted repeats (IRs) and two single-copy areas. The sizes of the large single-copy region and the small single-copy region were 84,657 and 18,109bp, respectively. The E. breviscapus cp genome consisted of 127 coding genes, including 83 protein coding genes, 36 transfer RNA (tRNA) genes, and eight ribosomal RNA (rRNA) genes. For those genes, 95 genes were single copy genes and 16 genes were duplicated in two inverted regions with seven tRNAs, four rRNAs, and five protein coding genes. Then, genomic DNA of E. breviscapus was used as a template, and the endogenous 5' and 3' flanking sequences of the trnI gene and trnA gene were selected as homologous recombinant fragments in vector construction and cloned through PCR. The endogenous 5' flanking sequences of the psbA gene and rrn16S gene, the endogenous 3' flanking sequences of the psbA gene, rbcL gene, and rps16 gene and one sequence element from the psbN-psbH chloroplast operon were cloned, and certain chloroplast regulatory elements were identified. Two homologous recombination fragments and all of these elements were constructed into the cloning vector pBluescript SK (+) to yield a series of chloroplast expression vectors, which harbored the reporter gene EGFP and the selectable marker aadA gene. After identification, the chloroplast expression vectors were transformed into Escherichia coli and the function of predicted regulatory elements was confirmed by a spectinomycin resistance test and fluorescence intensity measurement. The results indicated that aadA gene and EGFP gene were efficiently expressed under the regulation of predicted regulatory elements and the chloroplast expression vector had been successfully constructed, thereby providing a solid foundation for establishing subsequent E. breviscapus chloroplast transformation system and genetic improvement of E. breviscapus.

Characterization of the complete plastid genome of of Veronica eriogyne H. Winkl., a Tibetan medicinal herb

Veronica eriogyne H. Winkl.(Plantaginaceae) is a perennial herb with high medicinal value. To better understand the molecular genetics and evolutionary of V. eriogyne, its complete plastid genome was sequenced and annotated. The assembled chloroplast genome is a circular 151,083 bp sequence, consisting of a 82,302 bp large single copy region (LSC) and a 17,449 bp small single copy region (SSC), which were flanked by a pair of 25,666 bp inverted repeats (IRs). The GC content of the chloroplast genome is 38.03%. Moreover, a total of 134 functional genes were annotated, including 88 protein-coding, 38 tRNA, and 8 rRNA genes. Phylogenetic analysis showed that V. eriogyne has close relationship with V. persica Poi. The current study provides important information for further genetic studies on Plantaginacea.

The complete chloroplast genome of Ormosia purpureiflora (Fabaceae)

Ormosia purpureiflora is endemic to China. It is named after its purple flowers. It is a small tree only up to 3 m. It has leathery leaves, racemose inflorescences. The seeds are elliptic and red in coat. It is only confined to Luofushan Provincial Nature Reserve in Huizhou of Guangdong Province. Herein, we first reported on its complete chloroplast genome sequence as genomic resource for conservation purposes. The chloroplast genome of O. purpureiflora was 173,364 bp in length, with a large single-copy region of 73,465 bp, a small single-copy region of 18,751 bp, and a pair of inverted repeat regions that were 40,574 bp each. A total of 90 protein-coding genes, 38 transfer RNA genes, and eight ribosomal RNA genes were predicted, while 106 simple sequence repeats were recorded throughout the genome. Phylogenetic analysis revealed that O. purpureiflora was sister to O. emarginata.

The complete chloroplast genome of Yishui Lily 140 (Liliaceae Lilium lancifolium) yielded by next-generation sequencing

Yishui Lily 140 (Lilium lancifolium) is a hybrid lily species which was bred from wild lily varieties due to its edible and medicinal value. In this study, we have sequenced the complete chloroplast (cp) of L. lancifolium. The complete cp sequence is 152,643 bp long, with a large single copy (LSC) region of 82,084 bp, a small single copy (SSC) region of 17,513 bp, and two inverted repeat (IR) regions of 26,492 bp each. The GC contents of the complete cp genomes are 37.0%. It contains 132 genes, including 86 coding genes, 8 ribosomal RNAs, and 38 transfer RNAs. Among them, 16 different genes have a single intron and the remaining two genes have double introns, including nine cis-splicing and one trans-splicing genes. Compared with other species, we found three high variation hot spots and 96 repeats sequence. The genetic information of Lilium can be enriched as well as identifying proximal species. They are edible and have medicinal value for humans. Therefore, sequencing of Yishui Lily 140 is important to explore the cp genome composition.

The complete chloroplast genome and phylogenetic analysis of Artocarpus champeden

Artocarpus champeden Spreng. is a popular fruit tree, grown in tropical and subtropical regions. Besides food, A. champeden is also a medicinal plant with various medicinal properties. In this study, A. champeden chloroplast genome was sequenced, assembled, and annotated due to its rich information on species evolution and inter-species genetic relationships. The quadripartite structure of A. champeden complete chloroplast genome is 158,568 bp in length and comprises a large single-copy region (LSC) of 88,076 bp, a small single-copy region (SSC) of 19,028 bp, and two inverted repeat regions (IRa and IRb) of 25,732 bp. A total of 131 genes were annotated, including 85 protein-coding genes, 37 tRNA genes, eight rRNA genes, and one pseudogene. Phylogenetic analysis revealed a close relationship between A. champeden and A. heterophyllus. In addition, the study provides abundant genomic information for future phylogenetic studies of A. champeden and the Moraceae family.

The complete chloroplast genome of Saussurea medusa maxim. (Asteraceae), an alpine Tibetan herb

Saussurea medusa is an important traditional Tibetan medicinal plant in China. In this study, we assembled the complete chloroplast (cp) genome of S. medusa. The complete S. medusa chloroplast genome is a circular molecular structure of 152,257 bp in length with coding GC 37.93%, consisting of two inverted repeats (25,204 bp) separated by a large single-copy region (83,334 bp) and a small single-copy region (18,515 bp). The complete chloroplast genome of S. medusa contained 130 genes, including 87 protein-coding genes, 35 tRNA genes, and eight rRNA genes. Phylogenetic analysis shows that S. medusa is most closely related to Saussurea inversa and Saussurea pseudoleucoma. The complete chloroplast genome sequence of S. medusa facilitates the phylogenetic studies of Asteraceae.

Complete chloroplast genome of Loropetalum chinense var. rubrum and phylogenetic analysis from Baoshan, China

In this study, the complete chloroplast genome of Loropetalum chinense var. rubrum Yieh was sequenced and characterized. The chloroplast genome is 159,427 bp in length, and contains a large single-copy (LSC) region of 88,185 bp and a small single-copy (SSC) region of 18,772 bp separated by a pair of inverted repeat (IR) regions of 26,235 bp. There are 128 genes in the genome including 83 protein-coding, 37 tRNA, and eight rRNA genes. The overall GC is 38.0% and the LSC, SSC, and IR regions are 36.1, 32.7, and 43.1%, respectively. Phylogenetic analysis of L. chinense var. rubrum fully resolved it in a clade with L. subcordatum. This complete chloroplast genome will provide valuable insight into evolution, molecular breeding, and phylogenetic analysis of Loropetalum species.

The complete chloroplast genome of Asarum pulchellum Hemsl. (Aristolochiaceae: Asarum L.)

Asarum pulchellum Hemsley 1890, belonging to Aristolochiaceae family, is a kind of folk herb resource with certain toxicity. In this study, we acquired the complete chloroplast genome of A. pulchellum for its accurate species identification and phylogenetic analysis. The genome is 177,905 bp in size with a typical circular quadripartite structure, consisting of a large single-copy region, a small single-copy region and a pair of inverted repeats. In total, 136 genes were annotated, including 92 protein-coding genes, 36 tRNA genes and eight rRNA genes. In the phylogenetic analysis, A. pulchellum and A. sieboldii formed a sister clade. The chloroplast genome helps further studies of taxonomy and genetic evolution of Aristolochiaceae family.

The complete chloroplast genome sequence of the Cucurbita ficifolia Bouché (Cucurbitaceae)

Cucurbita ficifolia Bouché is an important germplasm resource used for rootstock and hypoglycemic food in Cucurbitaceae. The complete chloroplast genome sequence of C. ficifolia has been determined in this study. The total genome size is 157,533 bp in length and contains a pair of inverted repeats (IRs) of 25,639 bp, which were separated by large single copy (LSC) and small single copy (SSC) of 88,112 bp and 18,143 bp, respectively. A total of 130 genes were predicted including 86 protein-coding genes, eight rRNA genes and 36 tRNA genes. Further, Maximum-likelihood phylogenetic analysis revealed that C. ficifolia is a base clade of genus Cucurbita and closer to Cucurbita maxima. The chloroplast genome of C. ficifolia would promote the germplasm exploration, phylogenetic relationships, and molecular biology researches in Cucurbita.

Complete chloroplast genome sequence of Tamarix taklamakanensis (Tamaricaceae)

Tamarix taklamakanensis M. T. Liu, belonging to the genus Tamarix (family Tamaricaceae), is an endangered shrub endemic to arid basins in northwestern China. Most of species in this genus have high medicinal value. The complete chloroplast genome was reported in this study. The chloroplast genome with a total size of 156,177 bp consists of two inverted repeats (IR, 26,571 bp) separated by a large single-copy region (LSC, 84,778 bp) and a small single-copy region (SSC, 18,257 bp). Further annotation revealed the chloroplast genome contains 106 genes, including 73 protein coding genes, 29 tRNA genes, and 4 rRNA genes. A total of 64 simple sequence repeats (SSRs) were identified in the chloroplast genome. This information will be useful for study on the evolution and genetic diversity of T. taklamakanensis in the future.

The complete chloroplast genome of Epimedium fargesii Franch. (Berberidaceae), a rare plant species endemic to China

Epimedium L. is a medicinally important herbaceous genus in the family Berberidaceae. Epimedium fargesii Franch. is only narrowly inhabited in the Daba Mountains in China. Here, we sequenced and assembled the first complete chloroplast genome of Epimedium fargesii Franch. The chloroplast genome of E. fargesii was 157,208 bp in length, with a total GC content of 38.77%. A total of 112 unique genes were identified, including 78 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis indicated that E. fargesii formed a sister relationship with E. wushanense T. S. Ying. Our results provided fundamental data for further taxonomic and phylogenetic research of the genus Epimedium.

The complete chloroplast genome of Epimedium sutchuenense Franch. (Berberidaceae)

Epimedium L. is the largest herbaceous genus in the family Berberidaceae which comprises more than 60 species. Epimedium sutchuenense Franch. is narrowly inhabited in the Daba Mountains of China. In the current study, we assembled the first complete chloroplast genome of E. sutchuenense through Illumina paired-end sequencing. The complete chloroplast genome of E. sutchuenense was 157,218 bp in length and the total GC content was 38.78%. A total of 112 unique genes were identified, including 78 protein-coding genes, 30 tRNA genes and 4 rRNA genes. The phylogenetic analysis demonstrated that E. sutchuenense was sister to Epimedium wushanense T. S. Ying. Our results provided valuable information for further phylogenetic research and germplasm exploration of Epimedium genus.

The complete chloroplast genome of Epimedium platypetalum K. Mey. (Berberidaceae), a rare plant species from China

Epimedium L. is an important medicinal herbaceous genus in the family Berberidaceae. Epimedium platypetalum K. Mey. is a plant species only narrowly distributed in the western part of China. Here, the complete chloroplast genome of Epimedium platypetalum was assembled. The chloroplast genome of E. platypetalum was 159,088 bp in length, with a total GC content of 38.79%. A total of 112 unique genes were identified, among which 78 are protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic results revealed that E. platypetalum formed a sister relationship with E. membranaceum K. Mey. Our findings provided valuable data for future research on phylogenetic relationship and germplasm exploration within the genus Epimedium.

Plastid NDH Pseudogenization and Gene Loss in a Recently Derived Lineage from the Largest Hemiparasitic Plant Genus Pedicularis (Orobanchaceae)

The plastid genome (plastome) is highly conserved in both gene order and content and has a lower mutation rate than the nuclear genome. However, the plastome is more variable in heterotrophic plants. To date, most such studies have investigated just a few species or only holoheterotrophic groups, and few have examined plastome evolution in recently derived lineages at an early stage of transition from autotrophy to heterotrophy. In this study, we investigated the evolutionary dynamics of plastomes in the monophyletic and recently derived Pedicularis sect. Cyathophora (Orobanchaceae). We obtained 22 new plastomes, 13 from the six recognized species of section Cyathophora, six from hemiparasitic relatives and three from autotrophic relatives. Comparative analyses of gene content, plastome structure and selection pressure showed dramatic differences among species in section Cyathophora and in Pedicularis as a whole. In comparison with autotrophic relatives and other Pedicularis spp., we found that the inverted repeat (IR) region in section Cyathophora had expansions to the small single-copy region, with a large expansion event and two independent contraction events. Moreover, NA(D)H dehydrogenase, accD and ccsA have lost function multiple times, with the function of accD being replaced by nuclear copies of an accD-like gene in Pedicularis spp. The ccsA and ndhG genes may have evolved under selection in association with IR expansion/contraction events. This study is the first to report high plastome variation in a recently derived lineage of hemiparasitic plants and therefore provides evidence for plastome evolution in the transition from autotrophy to heterotrophy.

Characterization and comparative analysis of the plastome sequence from Justicia ventricosa (Lamiales: Acanthaceae)

Justicia ventricosa is a characteristic ethnic herb commonly used to treat Orthopedic pains. Here, to confirm its phylogenetic position and to develop molecular markers that can distinguish different Justicia species, we obtained and analyzed the plastome of Justicia ventricosa. The plastome was sequenced using the Illumina HiSeq sequencing platform, assembled with NOVOPlasty, and annotated with CPGAVAS2. The genome has a circular structure of 149,700 bp, containing a large single-copy region of 82,324 bp, a small single-copy region of 17,260 bp, and two reverse repeat regions of 25,058 bp each. It encodes 112 unique genes, including 76 protein-coding genes, eight ribosomal RNA genes, and 28 transfer RNA genes. Twenty cis-splicing genes were found. In total, we predicted 19 microsatellite repeats and 13 tandem repeat sequences. For distributed repeats, four were palindrome repeats and five were direct repeats. To find the highly variable intergenic spacer (IGS) regions, we calculated the K2P distances for IGS regions from four Justicia species. The K2P values ranged from 6.11 to 57.82. The largest K2P distances were found for ccsA-ndhD, petB-petD, psbK-psbI, and ycf4-cemA. Phylogenetic analysis results showed that J. ventricosa was most closely related to J. leptostachya. To determine how Justicia species adapt to the environment, we performed selection pressure analysis. Nine genes were found to have undergone positive selection. Lastly, we performed a genome-wise DNA barcode prediction, seven pairs of primers were found. The results provide valuable information that can be used for molecular marker development and bioprospecting in Justicia species.

Characterization of chloroplast genome of Eleusine coracana, a highly adaptable cereal crop with high nutritional reputation

Eleusine coracana (L.) Gaertn. is a kind of highly adaptable cereal crop with a high nutritional value with the reputation of ‘black pearl’. In this study, we sequenced, assembled and characterized the complete chloroplast genome of the grass species. The circular genome of E. coracana was 135,137 bp in length, which comprised two inverted repeat (IRa and IRb) regions of 20,919 bp in length separated by a large single copy (LSC) region of 80,663 bp and a small single copy (SSC) region of 12,636 bp. The total GC content of the E. coracana chloroplast genome was ∼38.13%. A total of 108 functional genes were predicted, including 76 protein-coding genes, 28 tRNA genes, and four rRNA genes. Our phylogenomic analysis of all protein-coding genes further revealed that E. coracana is closely related to Bouteloua curtipendula and B. gracilis, and they are together positioned in the subfamily Chloridoideae clade of the grass family.

The complete chloroplast genome of Cycas bifida, an extremely small population protected species

Cycas bifida (Dyer) K.D.Hill (2004) is an extremely small population-protected species of China. In this study, we reported the first chloroplast genome sequence of C. bifida. The chloroplast genome of C. bifida included two single-copy regions (large single-copy (LSC) and small single-copy (SSC)) and a pair of inverted repeats (IRs) regions comprising 88,946 bp, 23,107 bp, and 25,053 bp, respectively. The complete chloroplast genome of C. bifida contains 131 genes, including 86 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The overall GC content of the C. bifida chloroplast genome is 39.41%, and the LSC, SSC, and IR regions occupy 38.70%, 36.52%, and 42.02%, respectively. A phylogenetic analysis was performed based on complete chloroplast genomes from 15 species and found that C. bifida was closely related to Cycas szechuanensis W.C.Cheng & L.K.Fu.

The complete chloroplast of Chrysanthemum × morifolium ‘Fubaiju’

Chrysanthemum × morifolium ‘Fubaiju,’ which is native to Macheng, Hubei, China, has a long cultivation history almost dating back to the early 10th century Song dynasty, and is used as Chrysanthemum tea drink and Chinese traditional medicine. In this study, the complete chloroplast genome sequence of ‘Fubaiju’ was 151,109 bp, included a large single copy LSC (82,931 bp), a small single copy SSC (18,350 bp), and a pair of inverted repeat regions (24,941 bp). It contained 132 genes with 87 CDS, 8r RNA, and 37 tRNA. The phylogenetic analysis showed that the C. × morifolium ‘Fubaiju’ was clustered together with C. × morifolium ‘Baekma’.

Chloroplast genomic diversity in Bulbophyllum section Macrocaulia (Orchidaceae, Epidendroideae, Malaxideae): Insights into species divergence and adaptive evolution

Bulbophyllum is the largest genus in Orchidaceae with a pantropical distribution. Due to highly significant diversifications, it is considered to be one of the most taxonomically and phylogenetically complex taxa. The diversification pattern and evolutionary adaptation of chloroplast genomes are poorly understood in this species-rich genus, and suitable molecular markers are necessary for species determination and phylogenetic analysis. A natural Asian section Macrocaulia was selected to estimate the interspecific divergence of chloroplast genomes in this study. Here, we sequenced the complete chloroplast genome of four Bulbophyllum species, including three species from section Macrocaulia. The four chloroplast genomes had a typical quadripartite structure with a genome size ranged from 156,182 to 158,524 bp. The chloroplast genomes included 113 unique genes encoding 79 proteins, 30 tRNAs and 4 rRNAs. Comparison of the four chloroplast genomes showed that the three species from section Macrocaulia had similar structure and gene contents, and shared a number of indels, which mainly contribute to its monophyly. In addition, interspecific divergence level was also great. Several exclusive indels and polymorphism SSR loci might be used for taxonomical identification and determining interspecific polymorphisms. A total of 20 intergenic regions and three coding genes of the most variable hotspot regions were proposed as candidate effective molecular markers for future phylogenetic relationships at different taxonomical levels and species divergence in Bulbophyllum. All of chloroplast genes in four Bulbophyllum species were under purifying selection, while 13 sites within six genes exhibited site-specific selection. A whole chloroplast genome phylogenetic analysis based on Maximum Likelihood, Bayesian and Parsimony methods all supported the monophyly of section Macrocaulia and the genus of Bulbophyllum. Our findings provide valuable molecular markers to use in accurately identifying species, clarifying taxonomy, and resolving the phylogeny and evolution of the genus Bulbophyllum. The molecular markers developed in this study will also contribute to further research of conservation of Bulbophyllum species.

Characterization of the first chloroplast genome of Dichroa febrifuga and its phylogenetic analysis

Dichroa febrifuga, seen as a medicinal plant, has a long history in traditional Chinese medicine. In this study, we adopted Illumina Hiseq sequencing technology in order to determine the first complete chloroplast (cp) genome of D. febrifuga. The cp genome was 157,647 bp in length, including a large single-copy (LSC) region of 86,728 bp, a small single-copy (SSC) region of 18,675 bp, and a pair of inverted repeat (IR) regions of 26,122 bp. The genome encoded 128 genes, including 84 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. The phylogenetic analysis based on 20 complete cp genome sequences revealed that D. febrifuga was the sister of the ancestor of the reported Hydrangeeae species. The findings of the study will serve as a stepping stone for follow-up researches regarding the development of the D. febrifuga species.

First complete chloroplast genome of the rare medicinal plant Schnabelia tetrodonta

Schnabelia tetrodonta is a medicinal plant used in traditional Chinese medicine. However, the molecular biology data of the species was too scarce to bioprospect the medicinal species. In this study, the first complete chloroplast genome (cp) of S. tetrodonta was sequenced and assembled based on the next generation sequencing. The cp genome is 157,004 bp in length, including a large single-copy (LSC) region of 83,605 bp, a small single-copy (SSC) region of 36,899 bp, and a pair of inverted repeat (IR) regions of 18,250 bp each. The genome encodes 134 genes, including 90 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. The GC content of whole genome is 37.80%. The phylogenetic analysis based on 20 complete cp sequences (19 genome sequences from the Teucrioideae of Lamiaceae and an outgroup of Ipomoea purpurea) revealed that S. tetrodonta was closely related to S. oligophylla.

Complete chloroplast genome sequence of Chrysosplenium nudicaule (Saxifragaceae)

Chrysosplenium nudicaule Bunge, Tibetan name ‘Yajima,’ growing in the highlands of China is a perennial herb belonging to the genus Chrysosplenium Saxifragaceae. As a traditional Chinese medicine, it has been used to treat digestive diseases for hundreds of years. The complete chloroplast genome of Chrysosplenium nudicaule is 152,775 bp in length and comprises two inverted repeats (IR, 25,962 bp), a large single-copy region (LSC, 83,533 bp), and a small single-copy region (SSC, 17,318 bp). It harbors 112 genes, including 78 protein-coding genes, four ribosomal RNA genes, and 30 transfer RNA genes. In addition, the rpl32 gene was deleted. The GC content of the whole chloroplast genome is 37.54%. This chloroplast genome resource will be useful for study on the evolution and genetic diversity of C. nudicaule in the future.

Phylogenetic analysis and development of molecular markers for five medicinal Alpinia species based on complete plastome sequences

BACKGROUND

Alpinia species are widely used as medicinal herbs. To understand the taxonomic classification and plastome evolution of the medicinal Alpinia species and correctly identify medicinal products derived from Alpinia species, we systematically analyzed the plastome sequences from five Alpinia species. Four of the Alpinia species: Alpinia galanga (L.) Willd., Alpinia hainanensis K.Schum., Alpinia officinarum Hance, and Alpinia oxyphylla Miq., are listed in the Chinese pharmacopeia. The other one, Alpinia nigra (Gaertn.) Burtt, is well known for its medicinal values.

RESULTS

The four Alpinia species: A. galanga, A. nigra, A. officinarum, and A. oxyphylla, were sequenced using the Next-generation sequencing technology. The plastomes were assembled using Novoplasty and annotated using CPGAVAS2. The sizes of the four plastomes range from 160,590 bp for A. galanga to 164,294 bp for A. nigra, and display a conserved quadripartite structure. Each of the plastomes encodes a total of 111 unique genes, including 79 protein-coding, 28 tRNA, and four rRNA genes. In addition, 293-296 SSRs were detected in the four plastomes, of which the majority are mononucleotides Adenine/Thymine and are found in the noncoding regions. The long repeat analysis shows all types of repeats are contained in the plastomes, of which palindromic repeats occur most frequently. The comparative genomic analyses revealed that the pair of the inverted repeats were less divergent than the single-copy region. Analysis of sequence divergence on protein-coding genes showed that two genes (accD and ycf1) had undergone positive selection. Phylogenetic analysis based on coding sequence of 77 shared plastome genes resolves the molecular phylogeny of 20 species from Zingiberaceae. In particular, molecular phylogeny of four sequenced Alpinia species (A. galanga, A. nigra, A. officinarum, and A. oxyphylla) based on the plastome and nuclear sequences showed congruency. Furthermore, a comparison of the four newly sequenced Alpinia plastomes and one previously reported Alpinia plastomes (accession number: NC_048461) reveals 59 highly divergent intergenic spacer regions. We developed and validated two molecular markers Alpp and Alpr, based on two regions: petN-psbM and psaJ-rpl33, respectively. The discrimination success rate was 100 % in validation experiments.

CONCLUSIONS

The results from this study will be invaluable for ensuring the effective and safe uses of Alpinia medicinal products and for the exploration of novel Alpinia species to improve human health.

Characterization of the first chloroplast genome of Euchresta tubulosa Dunn and its phylogenetic analysis

Euchresta tubulosa Dunn not only is a national second-level protected wild plant in China, but also has a long history as a source plant in traditional Chinese medicine. The chloroplast (cp) genome of E. tubulosa was 154,102 bp, consisting of a large single-copy region (LSC: 92,877 bp), a small single-copy region (SSC: 36,645 bp), and a pair of inverted repeat regions (IRb and Ira: 12,290 bp, respectively). These sequences encoded 123 genes, including 78 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The phylogenetic analysis showed that E. tubulosa is close to Lupinus species.

The complete chloroplast genome of Callicarpa integerrima var. chinensis (Lamiaceae) from Guilin, China, a potential medicinal plant

Callicarpa integerrima var. chinensis is one of the traditional medical herbs which has the potential for multiple diseases’ treatment. In this study, the complete chloroplast genome sequence of C. integerrima var. chinensis was sequenced and assembled. A typical quadripartite structure was observed in the chloroplast genome of C. integerrima var. chinensis which was 154179 bp in length, including a pair of inverted repeat (IR) regions (each 51396 bp) separated by a large single-copy region (LSC) of 84927 bp and a small single-copy region (SSC) of 17856 bp, and the overall GC contents of the chloroplast genome was 38.08%. Additionally, we annotated 132 genes, including 86 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. Phylogenetic analysis was adopted which confirmed the position of C. integerrima var. chinensis was close to the congeneric C. formosana and C. siongsaiensis.

Biological Ingredient Analysis of Traditional Herbal Patent Medicine Fuke Desheng Wan Using the Shotgun Metabarcoding Approach

With the widespread use of traditional medicine around the world, the safety and efficacy of traditional herbal patent medicine have become an increasing concern to the public. However, it is difficult to supervise the authenticity of herbal materials in mixed herbal products according to the current quality standards, especially for traditional herbal patent medicine, with a distinct variance in the dosage of herbal materials. This study utilized the shotgun metabarcoding approach to analyze the biological ingredients of Fuke Desheng Wan (FKDSW), which is an effective traditional herbal product for the treatment of dysmenorrhea. Six herbal materials were collected, and a lab-made mock FKDSW sample was produced to establish a method for the authentication assessment of biological ingredients in traditional herbal patent medicine based on shotgun metabarcoding. Furthermore, four commercial FKDSW samples were collected to verify the practicality of the shotgun metabarcoding approach. Then, a total of 52.16 Gb raw data for 174 million paired-end reads was generated using the Illumina NovaSeq sequencing platform. Meanwhile, 228, 23, and 14 operational taxonomic units (OTUs) were obtained for the ITS2, matK, and rbcL regions, respectively, after bioinformatic analysis. Moreover, no differences were evident between the assembly sequences obtained via shotgun metabarcoding and their corresponding reference sequences of the same species obtained via Sanger sequencing, except for part of the ITS2 and matK assembly sequences of Paeonia lactiflora Pall., Saussurea costus (Falc.) Lipsch. and Bupleurum chinense DC. with 1–6 different bases. The identification results showed that all six prescribed ingredients were successfully detected and that the non-authentic ingredient of Bupleuri Radix (Chaihu, Bupleurum chinense DC. or Bupleurum scorzonerifolium Willd.) was found in all the commercial samples, namely Bupleurum falcatum L. Here, 25 weed species representing 16 genera of ten families were detected. Moreover, 26 fungal genera belonging to 17 families were found in both lab-made and commercial FKDSW samples. This study demonstrated that the shotgun metabarcoding approach could overcome the biased PCR amplification and authenticate the biological ingredients of traditional herbal patent medicine with a distinct variance in the dosage of the herbal materials. Therefore, this provides an appropriate evaluation method for improving the safety and efficacy of traditional herbal patent medicine.

The first complete plastome of Chimonobambusa quadrangularis (Fenzl) Makino: assembly, annotation and phylogenetic analysis

Chimonobambusa quadrangularis (Fenzl) Makino is one of the ‘Square Bamboo’ due to its square-shaped culm. However, as an edible bamboo, there is no genomic information reported so far. In this study, we reported and characterized the first plastome of C. quadrangularis based on Illumina Hiseq sequencing. The plastome exhibited a typical angiosperm circular structure, containing four regions: large single-copy region (LSC: 83,125 bp), small single-copy region (SSC: 12,811 bp), and a pair of inverted repeat regions (IR: 21,802 bp). The plastome consisted of 139,540 bp in size, with 82 protein-coding genes, 39 tRNA genes, and eight rRNA genes. The total nucleotide composition consisted of 30.16% A, 30.97% T, 19.25% C, and 19.63% G. The G + C content of the whole plastome was 38.88%. Phylogenetic analysis based on the complete plastomes of six species indicated that C. quadrangularis was closed to C. hejiangensis. The plastome is helpful for studying the evolution of beneficial adaptations and developing bioremediation and biomedical science.

Highly Diverse Shrub Willows (Salix L.) Share Highly Similar Plastomes

Plastome phylogenomics is used in a broad range of studies where single markers do not bear enough information. Phylogenetic reconstruction in the genus Salix is difficult due to the lack of informative characters and reticulate evolution. Here, we use a genome skimming approach to reconstruct 41 complete plastomes of 32 Eurasian and North American Salix species representing different lineages, different ploidy levels, and separate geographic regions. We combined our plastomes with published data from Genbank to build a comprehensive phylogeny of 61 samples (50 species) using RAxML (Randomized Axelerated Maximum Likelihood). Additionally, haplotype networks for two observed subclades were calculated, and 72 genes were tested to be under selection. The results revealed a highly conserved structure of the observed plastomes. Within the genus, we observed a variation of 1.68%, most of which separated subg. Salix from the subgeneric Chamaetia/Vetrix clade. Our data generally confirm previous plastid phylogenies, however, within Chamaetia/Vetrix phylogenetic results represented neither taxonomical classifications nor geographical regions. Non-coding DNA regions were responsible for most of the observed variation within subclades and 5.6% of the analyzed genes showed signals of diversifying selection. A comparison of nuclear restriction site associated DNA (RAD) sequencing and plastome data on a subset of 10 species showed discrepancies in topology and resolution. We assume that a combination of (i) a very low mutation rate due to efficient mechanisms preventing mutagenesis, (ii) reticulate evolution, including ancient and ongoing hybridization, and (iii) homoplasy has shaped plastome evolution in willows.

Analysis of the complete chloroplast genomes of Scutellaria tsinyunensis and Scutellaria tuberifera (Lamiaceae)

Scutellaria Linn. is a perennial herb with about 300 species. This genus has high medicinal value and many are used in Traditional Chinese Medicine (TCM). In this study, we sequenced and assembled the complete chloroplast genomes of Scutellaria tsinyunensis and S. tuberifera. Subsequently, we conducted a comprehensive comparative genomics analysis with 12 other published Scutellaria species. These genomes all had a conserved quartile structure, and the gene contents, gene sequences and GC contents are highly similar. The study on the genetic characteristics and nucleotide substitution rate of different genes found that the protein-coding genes of chloroplasts have differed greatly. Most genes are under purifying selection, but the rps12 gene may have undergone positive selection. Besides, we identified three hypervariable regions as potential markers for Scutellaria taxa, which could play an important role in species identification of Scutellaria. Phylogenetic analysis showed that the 14 Scutellaria taxa were divided into two major clades. Moreover, the variation of IR regions is closely related to the evolutionary history as was reconstructed based on SNPs. In conclusion, we provided two high-quality chloroplast reference genomes of Scutellaria, this reliable information and genomic resources are valuable for developing of efficient DNA barcodes as reconstruction of chloroplast evolutionary history of the genus.

Complete chloroplast genome and phylogenetic analysis of Glebionis coronaria (L.) Cass. ex Spach (Asteraceae)

Glebionis coronaria (Asteraceae) is widely distributed in China, and it regulates the stomach, strengthens the spleen, reduces blood pressure, and reinforces the brain. In this study, the complete chloroplast genome sequence of G. coronaria was reported. The total chloroplast genome cycle was 149,750 bp, and it formed a large single-copy (LSC, 82,290 bp), a small single-copy (SSC, 18,414 bp), and two inverted repeats (IR, 24,523 bp) regions. The GC content of this genome was 36.35%. The whole-genome contained 128 genes, including 84 protein-coding genes, 36 tRNA genes, and eight rRNA genes. Phylogenetic analysis indicated that G. coronaria appeared within a clade comprised of Chrysanthemum species.

The complete chloroplast genome of Asarum heterotropoides Fr. Schmidt var. mandshuricum (Maxim.) Kitag. (Aristolochiaceae), a traditional Chinese medicine herb

The complete chloroplast genome of A. heterotropoides var. mandshuricum reported herein was a circular DNA molecule of 160,262 bp in length. The typical quadripartite structure of the genome consisted of a pair of inverted repeats (IRs) of 27,262 bp separated by a large single-copy (LSC) region of 88,927 bp and a small single-copy region (SSC) of 16,811 bp. The overall GC content of the genome is 38.45%, with 36.7%, 33.1%, and 43.0% in LSC, SSC, IR regions, respectively. The cp genome encoded 125 genes, including 83 protein-coding genes, 34 tRNA genes, and 8 rRNA genes. 138 SSRs were identified in the genome. Phylogenetic anlysis showed the position of A. heterotropoides var. mandshuricum is closely related to A. heterotropoides.

The complete chloroplast genome of Epimedium flavum Stearn (Berberidaceae)

Epimedium flavum Stearn, which belongs to Berberidaceae, is mainly distributed in the Sichuan province of China. In this study, the complete chloroplast genome of E. flavum was reported for the first time. The whole genome of E. flavum was 159,134 bp in length, and revealed a typical quadripartite structure, including two copies of an inverted repeat (IR) region of 27,735 bp separating a large single-copy region (LSC, 86,576 bp) and a small single-copy region (SSC, 17, 088 bp). The chloroplast genome contained 112 unique genes, including 78 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Phylogenetic analysis showed that E. flavum of series Davidianae was firstly clustered with E. brevicornu of ser. Brachyerae.

The complete chloroplast genome of Cotyledon tomentosa Harv

Cotyledon tomentosa Harv. is a well-known succulent plant that have important ornamental and economic value. In this study, we release and detail the complete chloroplast genome sequences of C. tomentosa. The whole chloroplast genome was 149,729 bp in length and comprised 131 genes, including 84 protein-coding genes, 37 tRNA genes, eight rRNA genes. The C. tomentosa. chloroplast genome had a GC content of 38.23%. Phylogenetic analysis based on the complete chloroplast genomes showed that C. tomentosa had a close relationship with Kalanchoe tomentosa, Bryophyllum daigremontianum and Kalanchoe fedtschenkoi.

Characterization and Comparative Analysis of Complete Chloroplast Genomes of Three Species From the Genus Astragalus (Leguminosae)

Astragalus is the largest genus in Leguminosae. Several molecular studies have investigated the potential adulterants of the species within this genus; nonetheless, the evolutionary relationships among these species remain unclear. Herein, we sequenced and annotated the complete chloroplast genomes of three Astragalus species—Astragalus adsurgens, Astragalus mongholicus var. dahuricus, and Astragalus melilotoides using next-generation sequencing technology and plastid genome annotator (PGA) tool. All species belonged to the inverted repeat lacking clade (IRLC) and had similar sequences concerning gene contents and characteristics. Abundant simple sequence repeat (SSR) loci were detected, with single-nucleotide repeats accounting for the highest proportion of SSRs, most of which were A/T homopolymers. Using Astragalus membranaceus var. membranaceus as reference, the divergence was evident in most non-coding regions of the complete chloroplast genomes of these species. Seven genes (atpB, psbD, rpoB, rpoC1, trnV, rrn16, and rrn23) showed high nucleotide variability (Pi), and could be used as DNA barcodes for Astragalus sp. cemA and rpl33 were found undergoing positive selection by the section patterns in the coded protein. Phylogenetic analysis showed that Astragalus is a monophyletic group closely related to the genus Oxytropis within the tribe Galegeae. The newly sequenced chloroplast genomes provide insight into the unresolved evolutionary relationships within Astragalus spp. and are expected to contribute to species identification.