Complete Cp Genome Sequences Research Articles

The Complete Chloroplast Genome of Syzygium syzygioides (Myrtaceae: Myrtales) and Phylogenetic Analysis

Abstract Background: Syzygium syzygioides (Miq.) Merr. and L. M. Perry is a common medicinal plant species known for its biologically active compounds. However, the chloroplast (cp) genome of S. syzygioides has not been previously reported. This study aimed to determine the complete cp genome sequence of S. syzygioides and investigate its phylogenetic relationships within the Syzygium genus. Methods: Leaf samples of S. syzygioides were collected from Vietnam, and the complete cp genome was sequenced and assembled. Phylogenetic analyses were then conducted to examine the evolutionary relationships between S. syzygioides and other Syzygium species. Results: The cp genome of S. syzygioides was found to be 158,172 base pairs in length, with a GC content of 37.0%. Phylogenetic reconstruction based on the cp genome data revealed that S. syzygioides is closely related to 10 other Syzygium species, including Syzygium buettnerianum, Syzygium bamagense, Syzygium grande, Syzygium megacarpum, Syzygium glomeratum, Syzygium claviflorum, Syzygium tsoongii, Syzygium fluviatile, Syzygium buxifolium, and Syzygium grijsii. Conclusions: This study provides the first report of the complete cp genome sequence of S. syzygioides, a medicinally important plant species in the Myrtaceae family. The phylogenetic analysis using the cp genome data sheds light on the evolutionary relationships within the Syzygium genus, which is the largest genus in the Myrtaceae. The new molecular data generated in this study can be used for the molecular identification and further phylogenetic investigations of Syzygium species, contributing to a better understanding of the diversity and evolutionary history of this economically and ecologically significant plant group.

Characterization of the complete chloroplast genome sequence of <i>Hypericum petiolulatum</i> (Hypericaceae)

<i>Hypericum</i> L. (Hypericaceae) is one of the best-selling herbal medicines in the world comprising ca. 500 species of herbs, shrubs, and small trees. <i>Hypericum petiolulatum</i> Hook. f. & Thomson ex Dyer is widely distributed in China, Vietnam, Myanmar, Nepal, India, Malaysia, and Bhutan and is used as a traditional herb to treat hemoptysis and inflammation. In this study, we sequenced and assembled the complete chloroplast (cp) genome of <i>H. petiolulatum</i>. The complete plastome of <i>H. petiolulatum</i> was 136,105 bp in length, with a large single copy region (LSC) of 93,709 bp, a small single copy region (SSC) of 11088 bp and two identical inverted repeats (IRs) of 15,654 bp. The overall GC content of the plastome was 37.0%, while GC contents of the LSC, SSC, and each IR were 35.5%, 31.0%, and 43.8%, respectively. In addition, 116 genes consisting of 76 protein-coding genes, six ribosomal RNA genes, and 34 transfer RNA genes were identified. A phylogenetic analysis of 14 taxa inferred based on cp genome sequences revealed a close relationship between <i>H. petiolulatum</i> and <i>H. perforatum</i>. The complete cp genome sequence of <i>H. petiolulatum</i> reported in this paper will facilitate population and phylogenomics studies of this medicinal plant group.

The Complete Chloroplast Genomes of Bulbophyllum (Orchidaceae) Species: Insight into Genome Structure Divergence and Phylogenetic Analysis.

Bulbophyllum is one of the largest genera and presents some of the most intricate taxonomic problems in the family Orchidaceae, including species of ornamental and medical importance. The lack of knowledge regarding the characterization of Bulbophyllum chloroplast (cp) genomes has imposed current limitations on our study. Here, we report the complete cp genomes of seven Bulbophyllum species, including B. ambrosia, B. crassipes, B. farreri, B. hamatum, B. shanicum, B. triste, and B. violaceolabellum, and compared with related taxa to provide a better understanding of their genomic information on taxonomy and phylogeny. A total of 28 Bulbophyllum cp genomes exhibit typical quadripartite structures with lengths ranging from 145,092 bp to 165,812 bp and a GC content of 36.60% to 38.04%. Each genome contained 125-132 genes, encompassing 74-86 protein-coding genes, 38 tRNA genes, and eight rRNA genes. The genome arrangements, gene contents, and length were similar, with differences observed in ndh gene composition. It is worth noting that there were exogenous fragment insertions in the IR regions of B. crassipes. A total of 18-49 long repeats and 38-80 simple sequence repeats (SSRs) were detected and the single nucleotide (A/T) was dominant in Bulbophyllum cp genomes, with an obvious A/T preference. An analysis of relative synonymous codon usage (RSCU) revealed that leucine (Leu) was the most frequently used codon, while cysteine (Cys) was the least used. Six highly variable regions (rpl32-trnLUAG > trnTUGU-trnLUAA > trnFGAA-ndhJ > rps15-ycf1 > rbcL-accD > psbI-trnSGCU) and five coding sequences (ycf1 > rps12 > matK > psbK > rps15) were identified as potential DNA markers based on nucleotide diversity. Additionally, 31,641 molecular diagnostic characters (MDCs) were identified in complete cp genomes. A phylogenetic analysis based on the complete cp genome sequences and 68 protein-coding genes strongly supported that 28 Bulbophyllum species can be divided into four branches, sects. Brachyantha, Cirrhopetalum, and Leopardinae, defined by morphology, were non-monophyly. Our results enriched the genetic resources of Bulbophyllum, providing valuable information to illustrate the complicated taxonomy, phylogeny, and evolution process of the genus.

Molecular Characterization and Phylogenetic Analysis of Centipedegrass [Eremochloa ophiuroides (Munro) Hack.] Based on the Complete Chloroplast Genome Sequence.

Centipedegrass (Eremochloa ophiuroides) is an important warm-season grass plant used as a turfgrass as well as pasture grass in tropical and subtropical regions, with wide application in land surface greening and soil conservation in South China and southern United States. In this study, the complete cp genome of E. ophiuroides was assembled using high-throughput Illumina sequencing technology. The circle pseudomolecule for E. ophiuroides cp genome is 139,107 bp in length, with a quadripartite structure consisting of a large single copyregion of 82,081 bp and a small single copy region of 12,566 bp separated by a pair of inverted repeat regions of 22,230 bp each. The overall A + T content of the whole genome is 61.60%, showing an asymmetric nucleotide composition. The genome encodes a total of 131 gene species, composed of 20 duplicated genes within the IR regions and 111 unique genes comprising 77 protein-coding genes, 30 transfer RNA genes, and 4 ribosome RNA genes. The complete cp genome sequence contains 51 long repeats and 197 simple sequence repeats, and a high degree of collinearity among E. ophiuroide and other Gramineae plants was disclosed. Phylogenetic analysis showed E. ophiuroides, together with the other two Eremochloa species, is closely related to Mnesithea helferi within the subtribe Rottboelliinae. These findings will be beneficial for the classification and identification of the Eremochloa taxa, phylogenetic resolution, novel gene discovery, and functional genomic studies for the genus Eremochloa.

Characterization of the complete chloroplast genome sequence of Maesa japonica (Myrsinaceae)

Maesa Forssk. (Myrsinaceae) has approximately 200 species distributed in the tropics from southern Africa to East Asia. Among them, Maesa japonica (Thunb.) Moritzi ex Zoll. is distributed throughout China, Japan, Taiwan, Vietnam, and Korea. In Korea, this species is found only on Jejudo Island. In this study, we conducted whole-genome sequencing of M. japonica chloroplast (cp). The complete cp genome sequence of M. japonica was found to be 157,189 bp in length, consisting of large (87,780 bp) and small (18,143 bp) single-copy regions (LSC and SSC, respectively) and a pair of identical inverted repeats (IRs) (25,633 bp). The overall GC content of the cp genome was 38%, while those of the LSC, SSC, and each IR were 35.2%, 30.9%, and 43.1%, respectively. Furthermore, 130 genes consisting of 85 protein-coding genes, 37 transfer RNA genes and eight ribosomal RNA genes were identified in the cp genome. A phylogenetic analysis of 12 taxa inferred from the cp genome revealed a close relationship between M. salicifolia and M. japonica. The complete cp genome sequence of M. japonica provides valuable information for future evolutionary and phylogenetic studies of Maesa.

Complete chloroplast genome and phylogenetic analysis of Meliosma oldhamii Miq. ex Maxim. (Sabiaceae)

Meliosma oldhamii Miq. is a deciduous arbor and a member of Sabiaceae. It is one of the rare and protected plants with outstanding ornamental and economic value in Jiangsu, China. In addition to the resource values indicated above, there are numerous other elements that require additional research, including the chloroplast (cp) genomic information. In this work, the complete cp genome sequence of M. oldhamii was assembled and characterized for the first time. The complete cp genome of M. oldhamii was 159,950 base pair (bp) in length, including a large single-copy (LSC) region of 87,147 bp, a small single-copy (SSC) region of 18,015 bp, and the inverted repeats (IRs) region of 27,394 bp. It contains 131 genes, including 37 tRNA genes, eight rRNA genes, 85 protein-coding genes, and one pseudogene. The overall GC content of M. oldhamii cp genome was 37.95%. The placement of M. oldhamii in the phylogenetic tree constructed using the complete cp genome is largely congruent with previous studies. The clustering of Meliosma is non-monophyletic, aligns more closely with existing morphological taxonomic studies, thereby enhancing the scholarly and scientific nature of this research.

Development of InDels markers for the identification of cytoplasmic male sterility in Sorghum by complete chloroplast genome sequences analysis.

Cytoplasmic male sterility (CMS) is predominantly used for F1 hybrid breeding and seed production in Sorghum. DNA markers to distinguish between normal fertile (CMS-N) and sterile (CMS-S) male cytoplasm can facilitate F1 hybrid cultivar development in Sorghum breeding programs. In this study, the complete chloroplast (cp) genome sequences of CMS-S and Korean Sorghum cultivars were obtained using next-generation sequencing. The de novo assembled genome size of ATx623, the CMS-S line of the chloroplast, was 140,644bp. When compared to the CMS-S and CMS-N cp genomes, 19 single nucleotide polymorphisms (SNPs) and 142 insertions and deletions (InDels) were identified, which can be used for marker development for breeding, population genetics, and evolution studies. Two InDel markers with sizes greater than 20 bp were developed to distinguish cytotypes based on the copy number variation of lengths as 28 and 22 bp tandem repeats, respectively. Using the newly developed InDel markers with five pairs of CMS-S and their near isogenic maintainer line, we were able to easily identify their respective cytotypes. The InDel markers were further examined and applied to 1,104 plants from six Korean Sorghum cultivars to identify variant cytotypes. Additionally, the phylogenetic analysis of seven Sorghum species with complete cp genome sequences, including wild species, indicated that CMS-S and CMS-N contained Milo and Kafir cytotypes that might be hybridized from S. propinquum and S. sudanese, respectively. This study can facilitate F1 hybrid cultivar development by providing breeders with reliable tools for marker-assisted selection to breed desirable Sorghum varieties.

Comparison of Biological and Genetic Characteristics between Two Most Common Broad-Leaved Weeds in Paddy Fields: Ammannia arenaria and A. multiflora (Lythraceae).

Ammannia arenaria and A. multifloras, morphologically similar at the seedling stage, are the most common broad-leaved weeds in paddy fields. Our study showed that A. arenaria occupied more space than A. multifloras when competing with rice. However, A. multifloras germination has lower temperature adaptability. No difference in sensitivity to common herbicides between two Ammannia species was observed. Chloroplast (cp) genomes could be conducive to clarify their genetic relationship. The complete cp genome sequences of A. arenaria (158,401 bp) and A. multiflora (157,900 bp) were assembled for the first time. In A. arenaria, there were 91 simple sequence repeats, 115 long repeats, and 86 protein-encoding genes, one, sixteen, and thirty more than those in A. multiflora. Inverted repeats regions expansion and contraction and the phylogenetic tree based on cp genomes demonstrated the closely relationship between the two species. However, in A. arenaria, 20 single nucleotide polymorphisms in the CDS region were detected compared to A. multiflora, which can be used to distinguish the two species. Moreover, there was one unique gene, infA, only in A. arenaria. This study provides reliable molecular resources for future research focusing on the infrageneric taxa identification, phylogenetic resolution, population structure, and biodiversity of Ammannia species.

Molecular Structure and Variation Characteristics of the Plastomes from Six Malus baccata (L.) Borkh. Individuals and Comparative Genomic Analysis with Other Malus Species.

Malus baccata (L.) Borkh. is an important wild species of Malus. Its rich variation types and population history are not well understood. Chloroplast genome mining plays an active role in germplasm identification and genetic evolution. In this study, by assembly and annotation, six complete cp genome sequences, ranging in size from 160,083 to 160,295 bp, were obtained. The GC content of stable IR regions (42.7%) was significantly higher than that of full length (36.5%) and SC regions (LSC-34.2%, SSC-30.4%). Compared with other Malus species, it was found that there were more sites of polymorphisms and hotspots of variation in LSC and SSC regions, with high variation sites including trnR/UCU-atpA, trnT/UGU-trnL/UAA, ndhF-rpl32 and ccsA-ndhD. The intraspecific and interspecific collinearity was good, and no structural rearrangement was observed. A large number of repeating elements and different boundary expansions may be involved in shaping the cp genome size. Up to 77 or 78 coding genes were annotated in the cp genomes of M. baccata, and high frequency codons such as UUA (Leu), GCU (Ala) and AGA (Arg) were identified by relative synonymous codon usage analysis. Phylogeographic analysis showed that 12 individuals of M. baccata clustered into three different groups with complex structure, whereas variant xiaojinensis (M.H. Cheng & N.G. Jiang) was not closely related to M. baccata evolutionarily. The phylogenetic analysis suggested that two main clades of different M. baccata in the genus Malus were formed and that I and II diverged about 9.7 MYA. In conclusion, through cp genome assembly and comparison, the interspecific relationships and molecular variations of M. baccata were further elucidated, and the results of this study provide valuable information for the phylogenetic evolution and germplasm conservation of M. baccata and Malus.

Complete chloroplast genomes of five Cuscuta species and their evolutionary significance in the Cuscuta genus

BackgroundCuscuta, a parasitic plant species in the Convolvulaceae family, grows in many countries and regions. However, the relationship between some species is still unclear. Therefore, more studies are needed to assess the variation of the chloroplast (cp) genome in Cuscuta species and their relationship with subgenera or sections, thus, providing important information on the evolution of Cuscuta species.ResultsIn the present study, we identified the whole cp genomes of C. epithymum, C. europaea, C. gronovii, C. chinensis and C. japonica, and then constructed a phylogenetic tree of 23 Cuscuta species based on the complete genome sequences and protein-coding genes. The complete cp genome sequences of C. epithymum and C. europaea were 96,292 and 97,661 bp long, respectively, and lacked an inverted repeat region. Most cp genomes of Cuscuta spp. have tetragonal and circular structures except for C. epithymum, C. europaea, C. pedicellata and C. approximata. Based on the number of genes and the structure of cp genome and the patterns of gene reduction, we found that C. epithymum and C. europaea belonged to subgenus Cuscuta. Most of the cp genomes of the 23 Cuscuta species had single nucleotide repeats of A and T. The inverted repeat region boundaries among species were similar in the same subgenera. Several cp genes were lost. In addition, the numbers and types of the lost genes in the same subgenus were similar. Most of the lost genes were related to photosynthesis (ndh, rpo, psa, psb, pet, and rbcL), which could have gradually caused the plants to lose the ability to photosynthesize.ConclusionOur results enrich the data on cp. genomes of genus Cuscuta. This study provides new insights into understanding the phylogenetic relationships and variations in the cp genome of Cuscuta species.

Comparative study on chloroplast genomes of three Hansenia forbesii varieties (Apiaceae).

To find the gene hypervariable regions of three varieties of Hansenia forbesii H. Boissieu and determine their phylogenetic relationship, the chloroplast (cp) genome of these three varieties were firstly sequencing by the Illumina hiseq platform. In this study, we assembled the complete cp genome sequences of Hansenia forbesii LQ (156,954 bp), H. forbesii QX (157,181 bp), H. forbesii WQ (156,975 bp). They all contained 84 protein-coding genes, 37 tRNAs, and 8 rRNAs. The hypervariable regions between three cp genomes were atpF-atpH, petD, and rps15-ycf1. Phylogenetic analysis showed that H. forbesii LQ and H. forbesii WQ were closely related, followed by H. forbesii QX. This study showed that the three varieties of H. forbesii could be identified by the complete cp genome and specific DNA barcode (trnC-GCA-petN) and provided a new idea for germplasm identification of similar cultivated varieties.

Phylogenomic Analysis of Two Species of Parasenecio and Comparative Analysis within Tribe Senecioneae (Asteraceae)

The genus of Parasenecio (Senecioneae) comprises about 70 species of high medicinal value. In this study, the plastomes of Parasenecio palmatisectus and P. latipes were newly sequenced using high-throughput sequencing technology and compared with those of eight other species in Senecioneae. The complete chloroplast (cp) genomes were 151,185 bp in P. latipes with 37.5% GC and 151,263 bp in P. palmatisectus with 37.5% GC. We predicted 133 genes, including 37 tRNA genes, 86 protein-coding genes, 8 rRNA genes, and 2 pseudogenes (ycf1 and rps19). A comparative genomic analysis showed that the complete cp genome sequences of Parasenecio species and their related species were relatively conserved. A total of 49 to 61 simple sequence repeats (SSRs) and 34 to 46 interspersed repeat sequences were identified in the 10 Senecioneae species of plastomes. Within the tribe Senecioneae, single-copy regions were more variable than inverted repeats regions, and the intergenic regions were more variable than the coding regions. Two genic regions (ycf1 and ccsA) and four intergenic regions (trnC-GCA-petN, ycf1-trnN-GUU, psaI-ycf4, and rpl32-trnL-UAG) were identified as highly valuable plastid markers. A phylogenetic analysis under maximum likelihood revealed that the two Parasenecio species are sister to the genera of Ligularia and Sinosenecio in the tribe Senecioneae. This study also contributes to the super-barcode, phylogenetic, and evolutionary studies of Parasenecio plants.

The complete chloroplast genome of Elsholtzia fruticosa (D. Don) Rehd. (Labiatae), an ornamental plant with high medicinal value

Elsholtzia fruticosa is an ornamental plant with high medicinal value. In this study, we sequenced and analyzed the complete chloroplast (cp) genome of the species. The complete cp sequence is 151,550 bp, including the large single-copy (LSC) region of 82,778 bp, the small single-copy (SSC) region of 17,492 bp, and a pair of invert repeats (IRs) regions of 25,640 bp. It encodes 132 unique genes in total, including 87 protein-coding genes, 37 transfer RNA genes (tRNAs), and eight ribosomal RNA genes (rRNAs). The comparative analysis of complete cp genomes showed that the genomic structure and gene order of E. fruticosa cps were conserved. The sequences of rps15, rps19, ycf1, ycf3, ycf15, psbL, psaI, trnG-UCC, trnS-GCU, trnR-UCU, trnL-UAG, trnP-UG, and trnL-UAA serve as hotspots for developing the DNA barcoding of Elsholtzia species. There are 49 SSR loci in the cp genome of E. fruticosa, among which the repeat numbers of mononucleotide, dinucleotide, trinucleotide, tetranucleotide, and pentanucleotides SSR are 37, 9, 3, 0, and 0, respectively. A total of 50 repeats were detected, including 15 forward repeats, seven reverse repeats, 26 palindromic repeats, and two complementary repeats. Phylogenetic analysis based on the complete cp genome and protein-coding DNA sequences of 26 plants indicates that E. fruticosa has a dose relationship with E. splendens and E. byeonsanensis.

The complete chloroplast genome sequence of Castanopsis fordii Hance (Fagaceae)

Castanopsis fordii Hance 1884 is a typical evergreen broad-leaved forest plant in the south subtropical and middle subtropical regions of China. It has high utilization value in wood production and soil erosion protection. Here, we first reported and characterized the complete chloroplast (cp) genome sequence of C. fordii based on Illumina paired-end sequencing data. The complete cp genome sequence of C. fordii was 160,853 base pairs (bp) in length which contained two inverted repeats (IRs) of 25,699 bp separated by a large single-copy (LSC) and a small single copy (SSC) of 90,474 bp and 18,981 bp, respectively. The cpDNA contained 129 genes, comprising 85 protein-coding genes, 36 tRNA genes, 8 rRNA genes. The overall GC content of the plastome was 36.8%. Phylogenetic analysis base on 14 chloroplast genomes indicated that C. fordii was closely related to the species C. tibetana and C. concinna in Fagaceae.

Identification of Laportea bulbifera using the complete chloroplast genome as a potentially effective super-barcode.

Laportea bulbifera, a Miao medicine grown in karst areas, has exerted a unique curative effect on skin itching in the elderly, with an annual sales of > 100 million Yuan. Owing to the shortage of resources and large morphological variations in L. bulbifera, it is difficult to identify the species correctly using only traditional methods, which seriously affects the safety of drug usage for patients. This study obtained the complete high-quality L. bulbifera chloroplast (cp) genome, using second- and third-generation high-throughput sequencing. The cp genome was 149,911bp in length, with a typical quadripartite structure. A total of 127 genes were annotated, including 83 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. There was an inverted small single copy (SSC) structure in the L. bulbifera cp genome, one large-scale rearrangement of ~ 39kb excised in the SSC and IR regions. The complete cp genome sequence is used as a potentially effective super-barcode and the highly variable regions (ycf1, matK, and ndhD) can be used as potentially specific barcodes to accurately distinguish L. bulbifera from counterfeits and closely related species. This study is important for the identification of L. bulbifera and lays a theoretical foundation for elucidating the phylogenetic relationship of the species.

The complete chloroplast genome sequence of Camellia sinensis var. sinensis cultivar ‘FuDingDaBaiCha’

The complete chloroplast (cp) genome sequence of Camellia sinensis var. sinensis cultivar ‘FuDingDaBaiCha’ (FD), one of the key contributors to the history of tea breeding in China, was determined in this study. The cp genome of FD is 157,025 bp in length, including a large single-copy (LSC, 86,586 bp), a small single-copy (SSC, 18,277 bp), and a pair of inverted repeats (IRa and IRb, 26,081 bp). The overall GC content is 37.3%. A total of 137 genes were predicted, including 92 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis showed that FD was closely related to C. sinensis cv. ‘AnHua’, C. sinensis cv. ‘QianCha 1’, and C. sinensis cv. ‘BanTianYao’. The determination of the complete cp genome sequence of FD provides a way for the subsequent study of the genetic background and phylogenetic relationships of different tea plant cultivars.

Complete chloroplast genome sequence of <i>Clematis calcicola</i> (Ranunculaceae), a species endemic to Korea

The complete chloroplast genome (cp genome) sequence of <i>Clematis calcicola</i> J. S. Kim (Ranunculaceae) is 159,655 bp in length. It consists of large (79,451 bp) and small (18,126 bp) single-copy regions and a pair of identical inverted repeats (31,039 bp). The genome contains 92 protein-coding genes, 36 transfer RNA genes, eight ribosomal RNA genes, and two pseudogenes. A phylogenetic analysis based on the cp genome of 19 taxa showed high similarity between our cp genome and data published for <i>C. calcicola</i>, which is recognized as a species endemic to the Korean Peninsula. The complete cp genome sequence of <i>C. calcicola</i> reported here provides important information for future phylogenetic and evolutionary studies of Ranunculaceae.

Complete chloroplast genome and phylogenetic analysis of Anemone shikokiana.

Anemone shikokiana (Makino) Makino, disjunctly distributed in Shandong Peninsula of China and Shikoku Island of Japan, is a rare and endangered species. To provide genetic information and understand its phylogeny, we conducted research on the chloroplast (cp) genome of A. shikokiana. The complete cp genome sequence of A. shikokiana was constructed in this study. The results showed that the cp genome of A. shikokiana has a typical quadripartite cyclic with a total length of 159,286bp. In total, 111 unique genes were identified, including 78 protein-coding genes, 29 tRNA-coding genes and 4 rRNA-coding genes. A total of 37 long repeat sequences and 67 microsatellites were found in this cp genome. The cp genome of A. shikokiana was compared with eleven other Anemone cp genomes available from the Genbank database. We found some variations among the different genomes, especially in the LSC and SSC regions, and identified some regions as potential molecular markers such as ycf1, ndhE, ndhD, ndhF-trnL, ndhA and ndhF. The results of phylogenetic analysis suggested that A. narcissiflora was the closest relative of A. shikokiana. The results filled the gap of cp genome sequence information of A. shikokiana, laying the foundation to explore the evolutionary relationships of A. shikokiana in future studies. It provided a valuable genetic resource for the molecular identification and phylogenetic study of Anemone.

The Complete Chloroplast Genome Sequence of Machilus chuanchienensis (Lauraceae): Genome Structure and Phylogenetic Analysis

Machilus chuanchienensis is an ecological tree distributed in southwestern China. It has a significant valuation with making Hawk tea using its leaves, an ethnic traditional tea-like beverage with a long history in Chinese tea culture. The whole chloroplast (cp) genome is an ideal model for the phylogenetic study of Lauraceae because of its simple structure and highly conserved features. There have been numerous reports of complete cp genome sequences in Lauraceae, but little is known about M. chuanchienensis. Here, the next-generation sequencing (NGS) was used to sequence the M. chuanchienensis cp genome. Then, a comprehensive comparative genome analysis was performed. The results revealed that the M. chuanchienensis's cp genome measured 152,748 base pairs (bp) with a GC content of 39.15% and coded 126 genes annotated, including comprising eight ribosomal RNA (rRNA), 36 transporter RNA (tRNA), and 82 protein-coding genes. In addition, the cp genome presented a typical quadripartite structure comprising a large single-copy (LSC; 93,811) region, a small single-copy (SSC; 18,803) region, and the inverted repeats (IRs; 20,067) region and contained 92 simple sequence repeat (SSR) locus in total. Phylogenetic relationships of 37 species indicated that M. chuanchienensis was a sister to M. balansae, M. melanophylla, and M. minutiflora. Further research on this crucial species may benefit significantly from these findings.

Complete chloroplast genome of Paraphlomis koreana (Lamiaceae) – An endemic species from Korea

Paraphlomis is a genus belonging to the family Lamiaceae with approximately 24 species distributed mainly in East Asia. Among these, the distribution of one species, Paraphlomis koreana S.C. Ko et G.Y. Chung, is restricted to South Korea. Here, we determined the complete chloroplast (cp) genome of P. koreana and analyzed its relationship with related species. The complete cp genome sequence of P. koreana is 152,128 bp in length and consists of large (83,251 bp) and small (17,631 bp) single-copy regions and a pair of identical inverted repeats (25,623 bp). It contains 87 protein-coding genes, 37 tRNA genes, four rRNA genes, and one pseudogene ( infA ). Phylogenetic analysis of 22-related taxa inferred from cp genomes revealed the position of P. koreana (endemic to the Korean Peninsula) and showed that this species is closely related to P. javanica . The complete cp genome sequence of P. koreana obtained in this study provides important information for phylogenetic and evolutionary studies of Lamiaceae.