Circular Chloroplast Research Articles

The complete chloroplast genome sequence and phylogenetic analysis of Hordeum pusillum Nutt., 1818 (Poaceae)

Hordeum pusillum (Hordeum pusillum Nutt., 1818) is an annual barley that is native to the west of the North America and widespread in southern United States and tropical America. In this study, we have provided the first complete characterization of the chloroplast genome of H. pusillum. Our research revealed that the circular chloroplast genome of H. pusillum consists of a large single-copy region (LSC: 80,853 bp), a small single-copy region (SSC: 12,745 bp), and a pair of inverted repeat regions (IRs: 21,587 bp), totaling 136,772 bp in length. Within the chloroplast genome of H. pusillum, 91 protein-coding genes, 38 tRNA genes, and ten rRNA genes were identified. To determine the evolutionary relationship of Hordeum species with reported chloroplast genome sequences, we constructed a phylogenetic tree using the entire chloroplast genome sequences. The evolutionary position of H. pusillum corresponds to its geographical location. The chloroplast genome of H. pusillum provided in this study may have significant implications for the phylogenetic study of Poaceae species.

The complete chloroplast genome of Tabebuia rosea (Bignoniaceae)

Tabebuia rosea is a world-renowned woody plant with colorful flowers in full bloom. In addition to its high ornamental value, it also has ecological and medicinal value. In this study, the complete circular chloroplast genome of T. rosea was reconstructed and annotated using Illumina sequencing. The chloroplast genome was 158,919 bp in size with GC content of 38.21%, including a large single-copy region of 85,823 bp, a small single-copy region of 12,816 bp, and a pair of inverted repeats of 30,140 bp. It encoded 132 genes, including 87 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Based on current available chloroplast genome sequences, the phylogenetic analysis indicated that T. rosea was clustered with T. nodosa and H. chrysanthus. This study provided insights into the evolutionary relationships among different species of Bignoniaceae.

The Complete Chloroplast Genome Sequence of the Medicinal Moss Rhodobryum giganteum (Bryaceae, Bryophyta): Comparative Genomics and Phylogenetic Analyses.

Rhodobryum giganteum (Bryaceae, Bryophyta), a rare medicinal bryophyte, is valued for its cardiovascular therapeutic properties in traditional Chinese medicine. This study presents the first complete chloroplast genome sequence of R. giganteum, including its assembly and annotation. The circular chloroplast genome of R. giganteum is 124,315 bp in length, displaying a typical quadripartite structure with 128 genes: 83 protein-coding genes, 37 tRNAs, and 8 rRNAs. Analyses of codon usage bias, repetitive sequences, and simple sequence repeats (SSRs) revealed an A/U-ending codon preference, 96 repetitive sequences, and 385 SSRs in the R. giganteum chloroplast genome. Nucleotide diversity analysis identified 10 high mutational hotspots. Ka/Ks ratio analysis suggested potential positive selection in rpl20, rps18, petG, and psbM genes. Phylogenetic analysis of whole chloroplast genomes from 38 moss species positioned R. giganteum within Bryales, closely related to Rhodobryum laxelimbatum. This study augments the chloroplast genomic data for Bryales and provides a foundation for molecular marker development and genetic diversity analyses in medicinal bryophytes.

The complete chloroplast genome of Durio zibethinus L. cultivar Ri6 (Helicteroideae, Malvaceae)

Durian, a member of the Malvaceae family, is famous for its delicious fruits, which have strong scents and are rich in nutrients. In this study, we sequenced and characterized the complete chloroplast genome of Durio zibethinus L. 1774 cultivar Ri6, a popular durian cultivar in Vietnam, using the Illumina Hiseq platform. The results showed a circular chloroplast genome composed of a large single copy of 96,115 bp, a small single copy of 20,819 bp, and two inverted repeat regions of 24,185 bp. This genome consisted of 79 protein-coding genes, 30 transfer RNA genes, and four ribosomal RNA genes. The overall GC content of this genome was 35.7%. Phylogenetic analysis inferred from 78 protein-coding regions revealed monophyly of Durio species and a close relationship between D. zibethinus cultivar Ri6 and cultivar Mongthong. This study provides essential information for further studies examining genetic population, breedings, and species identification among Durio taxa and cultivars.

Complete chloroplast genome of Angelica hirsutiflora Liu et al. 1961 (Apiaceae)

Angelica hirsutiflora Liu et al.1961, is a perennial herb in the Apiaceae family that is endemic to Taiwan. In this study, the complete circular chloroplast genome of A. hirsutiflora was reconstructed and annotated using Illumina sequencing. The size of the chloroplast genome is 154,266 bp, consisting of two inverted repeats (IRs, 25,075 bp) separated by a large single-copy region (LSC, 86,569 bp) and a small single-copy region (SSC, 17,547 bp). The GC content of the chloroplast genome is 37.6%. There are 114 different genes in the chloroplast genome of A. hirsutiflora, including 80 protein-coding genes, 30 tRNA genes and four rRNA genes. A maximum-likelihood phylogenetic analysis showed that A. hirsutiflora forms a distinct clade, and separated from other species within the genus Angelica. This study provided insights into the evolutionary relationships among different species of Angelica.

A novel in-situ-process technique constructs whole circular cpDNA library

BackgroundThe chloroplast genome (cp genome) is directly related to the study and analysis of molecular phylogeny and evolution of plants in the phylogenomics era. The cp genome, whereas, is highly plastic and exists as a heterogeneous mixture of sizes and physical conformations. It is advantageous to purify/enrich the circular chloroplast DNA (cpDNA) to reduce sequence complexity in cp genome research. Large-insert, ordered DNA libraries are more practical for genomics research than conventional, unordered ones. From this, a technique of constructing the ordered BAC library with the goal-insert cpDNA fragment is developed in this paper.ResultsThis novel in-situ-process technique will efficiently extract circular cpDNA from crops and construct a high-quality cpDNA library. The protocol combines the in-situ chloroplast lysis for the high-purity circular cpDNA with the in-situ substitute/ligation for the high-quality cpDNA library. Individually, a series of original buffers/solutions and optimized procedures for chloroplast lysis in-situ is different than bacterial lysis in-situ; the in-situ substitute/ligation that reacts on the MCE membrane is suitable for constructing the goal-insert, ordered cpDNA library while preventing the large-insert cpDNA fragment breakage. The goal-insert, ordered cpDNA library is arrayed on the microtiter plate by three colonies with the definite cpDNA fragment that are homologous-corresponds to the whole circular cpDNA of the chloroplast.ConclusionThe novel in-situ-process technique amply furtherance of research in genome-wide functional analysis and characterization of chloroplasts, such as genome sequencing, bioinformatics analysis, cloning, physical mapping, molecular phylogeny and evolution.

Plastome diversity and evolution in mosses: Insights from structural characterization, comparative genomics, and phylogenetic analysis

Mosses play a significant role in ecology, evolution, and the economy. They belong to the nonvascular plant kingdom and are considered the closest living relatives of the first terrestrial plants. The circular chloroplast DNA molecules (plastomes) of mosses contain all the genetic information essential for chloroplast functions and represent the source of the evolutionary history of these organisms. This study comprehensively analyzed the plastomes of 47 moss species belonging to 14 orders, focusing on their size, GC content, gene loss, gene content, synteny, and evolution. The findings revealed great differences among plastome sizes, with Takakia lepidozioides (Takakiopsida) and Funaria hygrometrica (Funariales) having the largest and smallest plastomes, respectively. Moss plastomes included 69 to 89 protein-coding genes, 8 rRNA genes, and 34 to 42 tRNA genes, resulting in the total number of genes in a plastome ranging between 115 and 138. Various genes have been lost from the plastomes of different moss species, with Atrichum angustatum lacking the highest number of genes. This study also examined plastome synteny and moss evolution using comparative genomics and repeat sequence analysis. The results demonstrated that synteny and similarity levels varied across the 47 moss examined species, with some exhibiting structure similarity and others displaying structural inversions. Maximum likelihood and Bayesian approaches were used to construct a phylogenetic tree using 36 concatenated protein-coding genes, and the results revealed that the genera Sphagnum and Takakia are sister groups to the other mosses. Additionally, it was found that Tetraphidales, Polytrichales, Buxbaumiales, and Diphysciales are closely related. This research describes the evolutionary diversity of mosses and offers guidelines for future studies in this field. The findings also highlight the need for more investigations into the factors regulating plastome size variation in these plants.

The First Complete Chloroplast Genome of Cordia monoica: Structure and Comparative Analysis.

Cordia monoica is a member of the Boraginaceae family. This plant is widely distributed in tropical regions and has a great deal of medical value as well as economic importance. In the current study, the complete chloroplast (cp) genome of C. monoica was sequenced, assembled, annotated, and reported. This circular chloroplast genome had a size of 148,711 bp, with a quadripartite structure alternating between a pair of repeated inverted regions (26,897-26,901 bp) and a single copy region (77,893 bp). Among the 134 genes encoded by the cp genome, there were 89 protein-coding genes, 37 transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. A total of 1387 tandem repeats were detected, with the hexanucleotides class making up 28 percent of the repeats. Cordia monoica has 26,303 codons in its protein-coding regions, and leucine amino acid was the most frequently encoded amino acid in contrast to cysteine. In addition, 12 of the 89 protein-coding genes were found to be under positive selection. The phyloplastomic taxonomical clustering of the Boraginaceae species provides further evidence that chloroplast genome data are reliable not only at family level but also in deciphering the phylogeny at genus level (e.g., Cordia).

The complete chloroplast genome of <I>Erigeron canadensis</I> isolated in Korea (Asteraceae): Insight into the genetic diversity of the invasive species

We have determined the complete chloroplast genome of <i>Erigeron canadensis</i> isolated in Korea. The circular chloroplast genome of <i>E. canadensis</i> is 152,767 bp long and has four subregions: 84,317 bp of large single-copy and 18,446 bp of small single-copy regions are separated by 25,004 bp of inverted repeat regions including 133 genes (88 protein-coding genes, eight rRNAs, and 37 tRNAs). The chloroplast genome isolated in Korea differs from the Chinese isolate by 103 single-nucleotide polymorphisms (SNPs) and 47 insertions and deletion (INDEL) regions, suggesting different invasion sources of <i>E. canadensis</i> in Korea and China. A nucleotide diversity analysis revealed that the trend of the nucleotide diversity of <i>E. canadensis</i> followed that of 11 <i>Erigeron</i> chloroplasts, except for three peaks. The phylogenetic tree showed that our <i>E. canadensis</i> chloroplast is clustered with <i>E. canadensis</i> reported from China. <i>Erigeron canadensis</i> can be a good target when attempting to understand genetic diversity of invasive species.

The complete chloroplast genome of Viola grypoceras (Violaceae)

We constructed and characterized the chloroplast genome of Viola grypoceras via de novo assembly of Illumina data. The complete circular chloroplast genome is 158,357 bp long and contains four parts: a large single-copy (LSC) region of 86,764 bp, a small single-copy (SSC) region of 17,345 bp, and two inverted-repeat regions (IRa and IRb) of 27,124 bp each. Genome annotation predicted that this genome harbors 111 genes, comprising 77 protein-coding genes, 30 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. Phylogenetic analysis demonstrated that V. grypoceras shares a close systematic relationship with V. mirabilis and V. websteri by forming a basal clade in the genus Viola.

Comparative phylogenetic analysis of oolong tea (Phoenix Dancong tea) using complete chloroplast genome sequences

Phoenix Dancong tea, a variety of oolong tea, is produced in Chaozhou, Guangdong Province, China, and is characterized by numerous hybridizations and polyploidization. To assess the genetic diversity and phylogenetic relationships among Phoenix Dancong tea and other oolong teas, an integrated circular chloroplast genome was constructed for thirty species of Phoenix Dancong tea from Chaozhou. The genome of Phoenix dancong tea is a circular molecule of 157,041–157,137 bp, with a pair of inverted repeats (26,072-26,610 bp each) separated by a large single copy (86,615-86,658 bp) and small single copy (18,264-18,284 bp). A total of 135 unique genes were encoded, including 90 protein coding genes, 37 tRNAs and 8 rRNAs. A comparative analysis with the other seven species in the oolong tea family that have been sequenced to date revealed similarities in structural organization, gene content and arrangement. Repeated sequence analysis identified 17–23 tandem repeats, 20–24 forward repeats and 25–27 palindromic repeats. Additionally, a total of 65–70 simple sequence repeats were detected, with mononucleotide repeats being the most common. Phylogenetic analyses showed that Phoenix Dancong tea and Fujian oolong tea were clustered with other cultivated Camellia sinensis in the genus Camellia of the family Theaceae, while the two oolong tea species were relatively independently cross-embedded in the genus, Camellia. Close genetic relationships were observed between Phoenix Dancong tea and other oolong teas, and the overall chloroplast genomes of oolong tea showed patterns with low variations and conserved evolution. The availability of Phoenix Dancong tea chloroplast genomes not only elucidated the relationship among oolong teas from different origins in Guangdong and Fujian but also provided valuable genetic resources to assist further molecular studies on the taxonomic and phylogenomic resolution of the genus Camellia.

The complete chloroplast genome of Ziziphus jujuba cv. Bokjo (Rhamnaceae)

We have sequenced the Ziziphus jujuba cv. Bokjo chloroplast genome by de novo assembly using next-generation sequencing. The complete circular chloroplast genome consisted of 161,714 bp and contained four parts: a large single-copy (LSC) region of 89,323 bp, a small single-copy (SSC) region of 19,361 bp, and two inverted repeat regions (IRa and IRb) of 26,515 bp each. The genome annotation predicted a total of 110 genes, including 76 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis demonstrated the close taxonomic relationship between Z. jujuba cv. Bokjo and two other members of the Ziziphus genus, Z. spina-christi and Z. mauritiana. We found 135 polymorphic loci, 63 single nucleotide polymorphism (SNP) and 72 insertion–deletion (InDel), from the comparison of Z. jujuba cultivar Bokjo and Z. jujuba reference (NC_030299). The polymorphic loci could be used for the differentiation of Z. jujuba genetic resources and for breeding in the future.

Complete chloroplast genome and phylogenetic analysis of Bupleurum kaoi Liu, Chao, and Chuang, 1977: an endemic species in Taiwan

Bupleurum kaoi Liu, Chao, and Chuang is an endemic and endangered herb in Taiwan. In this study, the complete circular chloroplast genome of B. kaoi was reconstructed and annotated using Illumina sequencing. The genome size of B. kaoi is 155,938 bp, including a pair of inverted repeat regions (IRs: 26308 bp), separated by a large single-copy (LSC) region of 85,784 bp and a small single-copy (SSC) region of 17,538 bp. The GC content of the chloroplast genome is 37.6%. There are 113 different genes in the chloroplast genome of B. kaoi, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. A maximum-likelihood phylogenetic analysis showed that Bupleurum species is the monophyletic group, and B. kaoi belongs to subgenus Bupleurum and is closely related to B. scorzonerifolium.

Analysis and characterization of the chloroplast genome of Stephania cepharantha Hayata

Stephania cepharantha Hayata (S. cepharantha) is a common folk medicine herb in China with many therapeutic activities. This study used Illumina sequencing technology to construct a circular chloroplast genome map and compared it with that of other Stephania species. The genome of S. cepharantha is 158,052 bp in length, including a large single-copy region of 88,770 bp, a small single-copy region of 19,760 bp, and two reverse repeat regions of 49,522 bp. The genome encodes eight ribosomal ribonucleic acid (RNA) genes, 37 transfer RNA genes, and 85 protein-coding genes. Nucleotide variation analysis revealed that six highly variable regions of Stephania can be used as potential molecular markers for taxonomic research and evolutionary analysis. This study is the first chloroplast genome report on S. cepharantha, and it provides rich and valuable genetic information for understanding the evolutionary relationships and population inheritance of the species.

The complete chloroplast genome sequence of Begonia arachnoidea (Begoniaceae)

There are more than 2035 Begonia species (Begoniaceae) reported currently in the world. Begonia arachnoidea was found as a new species within a small area in Southern China. In this study, we are reporting for the first time its chloroplast genome for the purpose to compare with the chloroplast genomic data from other plant taxa which were closely related to this new species. Our results show that the circular chloroplast genome of B. arachnoidea is 169,725 bp in length, with 35.49% GC content. The whole structure of the genome has 76,431 bp in a large single-copy (LSC) region, 18,146 bp in a small single-copy (SSC) region, and the two inverted repeat (IRs) regions are both 37,574 bp. There are 90 protein-coding genes, 8 rRNA genes, and 42 tRNA genes encoded in this genome. Final phylogenetic analysis revealed that B. arachnoidea is genetically closest to B. pulchrifolia and B. coptidifolia.

The complete chloroplast genome sequence of Sloanea leptocarpa (Elaeocarpaceae) from China

Sloanea leptocarpa Diels, 1931 of the Elaeocarpaceae is an endemic plant from China distributed in subtropical evergreen broad-leaved forests and an excellent ornamental tree. The only available chloroplast genomic resource of the genus at present is that of S. sinensis (Hance) Hemsl., 1900 from eastern China. Here, we report the complete chloroplast genome sequence of S. leptocarpa which is less common than S. sinensis. The complete chloroplast genome of S. leptocarpa is 158,077 bp in length, and shows quadripartite organization including a pair of inverted repeat regions (IRs) (24,963 bp) that is divided by a large single-copy (LSC) region (88,519 bp) and a small single-copy (SSC) region (19,632 bp). The circular chloroplast genome of S. leptocarpa contains 119 unique genes, composed of 74 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis involving 52 species with complete chloroplast genomes supported that S. leptocarpa is closely related to S. sinensis. This finding is in agreement with previous studies in which Elaeocarpaceae belongs to Oxalidales instead of Malvales and provides additional evidence for the monophyly of the Sloanea, a sister clade of the Elaeocarpus.

The complete chloroplast genome of Lonicera acuminata Wall. and its phylogenetic analysis

Lonicera acuminata Wall. is a medicinal and edible homologous plant in folk medicine that displays excellent pharmacological activities. However, the phylogenetic relationship between L. acuminata and other related family members remains unclear. In this study, we assembled the chloroplast genome of L. acuminata. The circular chloroplast genome was 154,282 bp in size, including a large single-copy region of 88,373 bp and a small single-copy region of 18,455 bp, which were separated by two inverted repeat regions (23,727 bp each). A total of 128 genes were predicted, including 8 ribosomal RNAs, 37 transfer RNAs and 83 protein-coding genes. The phylogenetic analysis revealed that L. acuminata was clustered together with L. pampaninii, L. macranthoides and L. hypoglauca.

Characterization of the complete chloroplast genome of Pedicularis shansiensis (Orobanchaceae), an endemic species of China

The complete chloroplast genome sequence of Pedicularis shansiensis Tsoong was determined and described. The circular chloroplast genome is 151,902 bp in length and contains a large single-copy region of 83,180 bp, a small single-copy region of 17,284 bp and two inverted repeat regions of 25,719 bp. The chloroplast genome contains 132 genes, including 86 protein-coding, 8 rRNA, and 38 tRNA genes. Phylogenetic analysis shows Pedicularis species cluster together and P. shansiensis forms a clade with P. dissect.

Characterization of the complete chloroplast genome sequence of Gynostemma microspermum (Cucurbitaceae)

Gynostemma microspermum C. Y. Wu et S. K. Chen is an endemic creeping herbaceous species mainly distributed in dense forests on limestone in northwestern China. Here, the complete chloroplast genome sequence of G. microspermum was obtained by Illumina pair-end sequencing. The circular complete chloroplast genome of G. microspermum is 158,692 bp in length and contains a large single copy region (87,452 bp), a small single copy region (19,068 bp) and two short inverted repeat regions (26,086 bp). The genome sequence encodes 133 genes including 87 protein-coding genes, 37 transfer RNA genes, 8 ribosomal RNA genes and 1 pseudogene. The maximum likelihood (ML) phylogeny estimation shows that G. microspermum is sister to all other analyzed species of the genus Gynostemma with high bootstrap support.

Chloroplast genome analysis of Chrysotila dentata.

Chrysotila dentata is an ecologically important marine alga contributing to the coccolith formation. In this study, a complete chloroplast (cp DNA) genome of Chrysotila dentata was sequenced by using Illumina Hiseq and was analyzed with the help of a bioinformatics tool CPGAVAS2. The circular chloroplast genome of Chrysotila dentata has a size of 109,017bp with two inverted repeats (IRs) regions (4513bp each) which is a common feature in most land plants and algal species. The Chrysotila dentata cp genome consists of 61 identified protein-coding genes, 30 tRNA genes and 6 rRNAs with 21 microsatellites. The phylogenetic relationship with other select algal species revealed a close phylogeny of Chrysotila dentata with Phaeocystis antarctica. This is the first report of the cp genome analysis of genus Chrysotila and the results from this study will be helpful for understanding the genetic structure and function of chloroplast in other species of Chrysotila.