Complete Chloroplast Genome Sequence Research Articles

Chloroplast Genome Profiling and Phylogenetic Insights of the “Qixiadaxiangshui” Pear (Pyrus bretschneideri Rehd.1)

The “Qixiadaxiangshui” pear (Pyrus bretschneideri Rehd.1) is a highly valued cultivar known for its crisp texture, abundant juice, and rich aroma. In this study, we reported the first complete chloroplast genome sequence of the “Qixiadaxiangshui” pear, which is 159,885 bp in length with a GC content of 36.58%. The genome exhibits a typical circular quadripartite structure, comprising a large single-copy region (LSC), a small single-copy region (SSC), and a pair of inverted repeat regions (IRs). A total of 131 genes were identified, including 84 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. We also identified 209 simple sequence repeats (SSRs) and several mutation hotspots, such as ndhC-trnM-CAU and trnR-UCU-atpA, which can be applied in molecular identification and phylogenetic studies of Pyrus. Comparative genomic analysis showed high conservation among ten pear cultivars. Phylogenetic analysis indicated that the “Qixiadaxiangshui” pear is closely related to germplasm Dangshansuli, Wonwhang, and Yali, suggesting a recent common ancestor. These findings provided valuable insights into the genetic diversity and evolutionary dynamics of the Pyrus species and contribute to the conservation and breeding of pear germplasm resources.

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 sequences of nine melon varieties (Cucumis melo L.): lights into comparative analysis and phylogenetic relationships

Melon (Cucumis melo L.) is one of the most extensively grown horticulture crops of the world. Based on the morphological characters, melon was formerly divided into two subspecies, Cucumis melo ssp. melo and C. melo ssp. agrestis. However, the present methods are still inadequate to distinguish between them. The phylogenetic analysis based on chloroplast genome sequences could provide essential evidence for the classification of melon varieties. We sequenced the chloroplast genomes of nine different melon varieties by the Illumina Hiseq and performed bioinformatic analyses including repeat element analysis, genome comparison and phylogenetic analysis. The results showed that the melon chloroplast genome has a typical quadripartite structure that was conserved across the analyzed sequences. Its length ranges between 155, 558 and 156, 569 bp, with a total GC content varying from 36.7% to 37%. We found 127–132 genes in melon chloroplast genomes, including 85–87 protein-coding regions, 34–37 tRNA and 6-8 rRNA genes. The molecular structure, gene order, content, codon usage, long repeats, and simple sequence repeats (SSRs) were mostly conserved among the nine sequenced genomes. Phylogenetic analysis showed that the chloroplast genome could clearly distinguish between C. melo ssp. melo and C. melo ssp. agrestis. This study not only provides valuable knowledge on melon chloroplasts, but also offers a theoretical basis and technical support for the genetic breeding of melons.

The chloroplast genome of a subtropical tree Sassafras randaiense (Hayata) Rehder, 1920 (Lauraceae)

The complete chloroplast genome sequence of Sassafras randaiense (Hayata) Rehder, 1920, a subtropical tree in the family Lauraceae, was determined. For a better understanding of the differences between S. randaiense and S. tzumu, the complete chloroplast genome of S. randaiense was sequenced and analyzed. The complete chloroplast genome is 151,781 bp in length, consisting of a pair of inverted repeat (IR) regions of 20,114 bp, one large single-copy (LSC) region of 92,740 bp, and one small single-copy (SSC) region of 18,813 bp. The overall GC content of the complete chloroplast genome is 39.2%. Further, maximum-likelihood phylogenetic analysis was conducted using 31 complete plastome sequences, which support that S. randaiense and S. tzumu are nested among the members of Cinnamomum, suggesting that Sassafras belongs to Cinnamomum.

<i>In silico</i> comparative analysis of the complete chloroplast genome sequences in the mulberry family (Moraceae)

<i>In silico</i> comparative analysis of the complete chloroplast genome sequences in the mulberry family (Moraceae)

Complete chloroplast genome of Saxifraga fortunei var. pilosissima (Saxifragaceae) endemic to Ulleung-do island, Korea

The Saxifraga fortunei var. pilosissima Nakai is an endemic species to Ulleung-do island. Here we report the complete chloroplast genome sequence of S. fortunei var. pilosissima, which was 151,186 bp in total length with the large single copy (LSC) region of 83,536 bp, the small single copy (SSC) region of 17,644 bp, and two inverted repeat (IR) regions of 25,003 bp. The chloroplast genome contained 131 genes, including 86 protein-coding, 37 tRNA, 8 rRNA genes, and GC content was 37.8%. Additionally, we found that the chloroplast genome of S. fortunei var. pilosissima exhibited intron loss in the rpl2 gene. Within the IR region, six protein-coding genes, seven tRNA genes, and four rRNA genes were duplicated. In the chloroplast genome of S. fortunei var. pilosissima, there are a total of 17 genes containing introns. Among them, 15 genes contain one intron each, while two genes contain two introns. Phylogenetic analysis based on 37 representative chloroplast genomes of the Saxifragaceae suggested that genus Saxifraga is monophyletic and S. fortunei var. pilosissima is placed in sect. Irregulares Haw. and grouped with S. fortunei, S. rufescens, and S. stolonifera with a strong maximum likelihood bootstrap support value.

Assembly and Comparative Analyses of the Chloroplast Genomes of the Threatened Plant Rosa anemoniflora

Due to insufficient molecular biology and genetic research on Rosa anemoniflora, this endangered plant has not yet received effective protection. Therefore, the complete chloroplast genome sequence of R. anemoniflora, along with comparative analysis of the chloroplast genomes of related species, is necessary and crucial for reconstructing phylogenetic relationships and developing genetic markers to conserve these species. A series of analyses, including genome structure, GC content, gene number, selection pressure, and nucleotide diversity, were performed by comparing the chloroplast genomes of R. anemoniflora and its relatives. The results indicate that the chloroplast genomes of R. anemoniflora and its close relatives are highly conserved in all genome characteristics, and all protein-coding genes in R. anemoniflora have not experienced significant positive or negative selection pressures. Comparative analysis revealed several variation hotspots, such as the atpH-atpI region, which can serve as a DNA barcode for distinguishing R. anemoniflora from its close relatives. Finally, the results confirmed that R. anemoniflora belongs to Rosa section Synstylae and that R. anemoniflora and its close relatives likely originated from the Fujian and Taiwan regions of China and diverged approximately 3.24 million years ago. This study provides crucial information for future biodiversity conservation and genetic resource management.

The complete chloroplast genome of Oxytropis ochrocephala Bunge 1874 (Fabaceae) and its phylogenetic analysis

This study presents the first-ever complete chloroplast (cp) genome sequence of Oxytropis ochrocephala Bunge 1874, a member of the Fabaceae family. The cp genome spans 126,996 base pairs and includes 109 genes, comprising 76 protein-coding genes, 29 tRNA genes, and four rRNA genes. Notably, the genome lacks an inverted repeat (IR) region. Additionally, we constructed phylogenetic trees for 34 species within Trib. Galegeae, employing both maximum likelihood (ML) and Bayesian inference (BI) methods. These analyses robustly support the monophyly of the Oxytropis species, evidenced by high bootstrap values (BP = 100) and posterior probabilities (PP = 1). Within this clade, O. ochrocephala exhibits a sister relationship with other Oxytropis species. Our findings provide valuable insights into the genetic makeup and evolutionary relationships of O. ochrocephala within the Galegeae tribe.

The complete chloroplast genome sequence and phylogenetic analysis of the Bichetii grass Chlorophytum laxum (Asparagaceae)

Chlorophytum laxum of Asparagaceae is a valuable ornamental plant native to the tropical regions of Asia, Africa, and Australia. The plant also has medicinal properties and is used as source for folk medicine. Despite being commercially important, genetic studies of C. laxum are still limited. To expand the genomic information of this plant species, we sequenced, assembled, and characterized its complete chloroplast genome. The chloroplast genome was 153,678 bp in length, with a large single-copy region (83,225 bp) and a small single-copy region (18,031 bp) separated by a pair of inverted repeat regions (26,211 bp each). A total of 127 genes were predicted, including 81 protein-coding, 38 tRNA, and eight rRNA genes. The overall GC content was 37.3%. Based on current sampling size, phylogenetic analysis using the maximum likelihood based on the complete chloroplast genome sequence revealed that the relationship in Chlorophytum is well resolved; C. laxum was closely related to C. rhizopendulum.

Complete Chloroplast Genome Sequence Structure and Phylogenetic Analysis of Kohlrabi (Brassica oleracea var. gongylodes L.).

Kohlrabi is an important swollen-stem cabbage variety belonging to the Brassicaceae family. However, few complete chloroplast genome sequences of this genus have been reported. Here, a complete chloroplast genome with a quadripartite cycle of 153,364 bp was obtained. A total of 132 genes were identified, including 87 protein-coding genes, 37 transfer RNA genes and eight ribosomal RNA genes. The base composition analysis showed that the overall GC content was 36.36% of the complete chloroplast genome sequence. Relative synonymous codon usage frequency (RSCU) analysis showed that most codons with values greater than 1 ended with A or U, while most codons with values less than 1 ended with C or G. Thirty-five scattered repeats were identified and most of them were distributed in the large single-copy (LSC) region. A total of 290 simple sequence repeats (SSRs) were found and 188 of them were distributed in the LSC region. Phylogenetic relationship analysis showed that five Brassica oleracea subspecies were clustered into one group and the kohlrabi chloroplast genome was closely related to that of B. oleracea var. botrytis. Our results provide a basis for understanding chloroplast-dependent metabolic studies and provide new insight for understanding the polyploidization of Brassicaceae species.

The complete chloroplast genome sequence and phylogenetic relationship analysis of Eomecon chionantha, one species unique to China.

Eomecon chionantha Hance, an endemic species in China, has a long medical history in Chinese ethnic minority medicine and is known for its anti-inflammatory and analgesic effects. However, studies of E. chionantha are lacking. In this study, we investigated the characteristics of the E. chionantha chloroplast genome and determined the taxonomic position of E. chionantha in Papaveraceae via phylogenetic analysis. In addition, we determined molecular markers to identify E. chionantha at the molecular level by comparing the chloroplast genomes of E. chionantha and its closely related species. The complete chloroplast genomic information indicated that E. chionantha chloroplast DNA (178,808bp) contains 99 protein-coding genes, 8 rRNAs, and 37 tRNAs. Meanwhile, we were able to identify a total of 54 simple sequence repeats through our analysis. Our findings from the phylogenetic analysis suggest that E. chionantha shares a close relationship with four distinct species, namely Macleaya microcarpa, Coreanomecon hylomeconoides, Hylomecon japonica, and Chelidonium majus. Additionally, using the Kimura two-parameter model, we successfully identified five hypervariable regions (ycf4-cemA, ycf3-trnS-GGA, trnC-GCA-petN, rpl32-trnL-UAG, and psbI-trnS-UGA). To the best of our knowledge, this is the first report of the complete chloroplast genome of E. chionantha, providing a scientific reference for further understanding of E. chionantha from the perspective of the chloroplast genome and establishing a solid foundation for the future identification, taxonomic determination and evolutionary analysis of this species.

The complete chloroplast genome of Eremurus zoae Vved. (Asphodelaceae), an endemic species of Kyrgyz Republic

Eremurus zoae Vved. 1971 is a perennial herbaceous plant in the family Asphodelaceae and an endemic species of the Kyrgyz Republic; however, its complete chloroplast genome sequence has not been reported. Here, we investigated the complete chloroplast (cp) genome of E. zoae using next-generation sequencing. The cp genome was 153,744 bp long, with a large single copy (84,020 bp), a small single copy (16,766 bp), and a pair of inverted repeats (26,479 bp). The genome encodes 132 genes, including 86 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. Phylogenetic analysis revealed that the genus Eremurus forms a monophyletic group and E. zoae is closely related to E. chinensis. This study provides a molecular foundation for future phylogenetic studies of Eremurus.

The complete chloroplast genome sequence of Zanthoxylum ailanthoides Sieb. et. Zucc (Rutaceae): an important medicinal plant

Zanthoxylum ailanthoides is a deciduous tree, with important medicinal and economic values. The complete chloroplast genome sequence of Z. ailanthoides was assembled and the phylogenetic relationship to other species was inferred in this study. The chloroplast genome is 157,209 bp in length, including two inverted repeats of 26,408 bp, a large single-copy of 86,099 bp and a small single copy of 18,294 bp. Moreover, the chloroplast genome contains 129 genes, including 84 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The overall GC content of the chloroplast genome is 38.4%. The phylogenetic analysis indicated that Z. ailanthoides was grouped with a clade containing the species of Z. multijugum, Z. calcicola, Z. oxyphyllum, Z. stenophyllum, and the genus was closely related to Phellodendron. This study contributes to a better understanding of the phylogenetic relationships among Zanthoxylum species.

The complete chloroplast genome sequence and phylogenetic analysis of Strobilanthes dalzielii (W.W.Sm.) Benoist 1935 (Acanthaceae)

Strobilanthes dalzielii of Acanthaceae is an herb species with potentially extensive applications for its pharmaceutical and ornamental values. Due to taxonomic complications and limited genetic information, the structural characteristics, and phylogenetic relationships of the S. dalzielii chloroplast genome were assembled and characterized here for the first time. The complete chloroplast genome of S. dalzielii was 144,580 bp in length. The genome is quadripartite in structure and consists of a large single-copy region (92,137 bp) and a small single-copy region (17,669 bp), which are separated by a pair of inverted repeats (each 17,387 bp). A total of 125 genes were annotated, including 80 protein-coding, 37 transfer RNA, and eight ribosomal RNA genes. The overall GC content was 36.4%. Phylogenetic analysis based on the complete chloroplast genome sequence of 21 taxa within the tribe Ruellieae of Acanthaceae using the maximum likelihood and Bayesian inference methods revealed that Strobilanthes diverged after Ruellia; S. dalzielii is closely related to S. tonkinensis. The genomic data obtained from this study will serve as valuable information to the species delimitation and genetic classification of Strobilanthes.

Chloroplast genomes in seven Lagerstroemia species provide new insights into molecular evolution of photosynthesis genes.

Lagerstroemia indica is an important commercial tree known for the ornamental value. In this study, the complete chloroplast genome sequence of Lagerstroemia indica "Pink Velour" (Lagerstroemia "Pink Velour") was 152,174bp in length with a GC content of 39.50%. It contained 85 protein coding genes (PCGs), 37 tRNAs, and 8 rRNA genes. 207 simple sequence repeats (SSRs) and 31 codons with relative synonymous codon (RSCU)value > 1 were detected. Phylogenetic analysis divided 10 Lagerstroemia species into evolutionary branches of clade A and clade B. We conducted a comparative analysis of Lagerstroemia "Pink Velours" complete chloroplast genome with the genomes of six closely related Lagerstroemia species from different origins. The structural features of all seven species were similar, except for the deletion of ycf1 nucleobases at the JSA boundary. The large single-copy (LSC) and the small single-copy (SSC) had a higher sequence divergence than the IR region, and 8 genes that were highly divergent (trnK-UUU, petN, psbF, psbJ, ndhE, ndhD, ndhI, ycf1) had been identified and could be used as molecular markers in future studies. High nucleotide diversity was present in genes belonging to the photosynthesis category. Mutation of single nucleic acid was mainly influenced by codon usage. The value percentage of nonsynonymous substitutions (Ka) and synonymous substitutions (Ks) in 6 Lagerstroemia species revealed that more photosynthesis genes have Ka or Ks only in Lagerstroemia fauriei, Lagerstroemia limii, and Lagerstroemia subcostata. These advances will facilitate the breeding of closely related Lagerstroemia species and deepen understanding on climatic adaptation of Lagerstroemia plants.

Complete chloroplast genomes of three copal trees (Bursera: Bullockia): comparative analysis and phylogenetic relationships.

Bursera trees are conspicuous elements of the tropical dry forests in the Neotropics that have significant cultural value due to their fragrant resins (incense), wood sources (handcrafts), and ecological benefits. Despite their relevance, genetic resources developed for the genus are scarce. We obtained the complete chloroplast (Cp) genome sequence, analyzed the genome structure, and performed functional annotation of three Bursera species of the Bullockia section: Bursera cuneata, B. palmeri, and B. bipinnata. The Cp genome sizes ranged from 159,824 to 159,872bp in length, including a large single-copy (LSC) region from 87,668 to 87,656bp, a small single-copy (SSC) from 18,581 to 18,571bp, and two inverted repeats regions (IRa and IRb) of 26,814bp each. The three Cp genomes consisted of 135 genes, of which 90 were protein-coding, 37 tRNAs, and 8 rRNAs. The Cp genomes were relatively conserved, with the LSC region exhibiting the greatest nucleotide divergence (psbJ, trnQ-UCC, trnG-UCC, and petL genes), whereas few changes were observed in the IR border regions. Between 589 and 591 simple sequence repeats were identified. Analysis of phylogenetic relationships using our data for each Cp region (LSC, SSC, IRa, and IRb) and of seven species within Burseraceae confirmed that Commiphora is the sister genus of Bursera. Only the phylogenetic trees based on the SSC and LSC regions resolved the close relationship between B. bipinnata and B. palmeri. Our work contributes to the development of Bursera's genomic resources for taxonomic, evolutionary, and ecological-genetic studies.

Chloroplast Genome-Wide Analysis Reveals New Single-Nucleotide Polymorphism Resources for the ARMS-qPCR Identification of Dendrobium brymerianum

Dendrobium brymerianum Rchb. f. is a species of orchid with pharmacological interest for its potential to inhibit the growth of human lung cancer cells. The identification of the Dendrobium species is a notable problem due to morphological similarities and the limitations of universal DNA barcodes. To overcome these difficulties, this study employed complete chloroplast (cp) genome sequences as useful resources for the identification of D. brymerianum. Based on Illumina sequencing, the complete cp genomes of five D. brymerianum individuals were assembled. These genomes were in the quadripartite structure, diverse in length between 151,832 and 152,189 bp, and comprised 126 genes. Moreover, significant differences were found in the Small Single-Copy (SSC) and Large Single-Copy (LSC) regions in comparison to the Inverted Repeat (IR) regions. This study recognized hotspot regions and simple sequence repeat (SSR) loci, providing valuable insights into genetic markers. The phylogenetic relationship of Dendrobium species was discovered, highlighting the need for more precise differentiation practices. To address this, ARMS-specific primers, mainly AAob1/AAob2, confirmed strong specificity, permitting the accurate identification of D. brymerianum from other species through ARMS-qPCR. Overall, this study of D. brymerianum chloroplast genomes has generated valuable data about sequence variations, phylogenetics, and mutation dynamics. These perceptions will be valuable in future research on population genetics, taxonomy, and species identification within the Dendrobium genus.

Elucidating phylogenetic relationships within the genus Curcuma through the comprehensive analysis of the chloroplast genome of Curcuma viridiflora Roxb. 1810 (Zingiberaceae)

Curcuma viridiflora Roxb., a plant species of significant pharmaceutical interest, has been the subject of limited chloroplast genomic research. In this study, we present the sequencing and assembly of the C. viridiflora chloroplast genome, which is characterized by a circular chromosome spanning 162,212 base pairs and a GC content of 36.20%. The genome encodes 87 protein-coding genes (PCGs), 38 transfer RNA (tRNA) genes, and eight ribosomal RNA (rRNA) genes. A phylogenetic analysis was conducted, incorporating eight related species, and based on the complete chloroplast genome and protein-coding DNA sequences of six related taxa within the genus. Outgroup species Zingiber zerumbet and Zingiber officinale were also included in the analysis. The results indicate a close relationship between C. viridiflora and Curcuma phaeocaulis, Curcuma sichuanensis, and Curcuma yunnanensis. This study provides the first chloroplast genome of C. viridiflora, thereby contributing a valuable genomic resource for future research on medicinal plants within the Curcuma genus.

The complete chloroplast genome of Hemiboea pterocaulis (Gesneriaceae) exclusively distributed in Guilin, Guangxi, China

Hemiboea pterocaulis is a unique species only found in Guilin, Guangxi, China. In this study, we sequenced and assembled the complete chloroplast genome of H. pterocaulis and revealed its phylogenetic relationship with other Hemiboea species. The chloroplast genome sequence of H. pterocaulis is 153,159 bp in length and comprises a large single-copy (LSC) region of 84,178 bp, a small single-copy (SSC) region of 18,087 bp, and a pair of inverted repeat (IR) regions, each with a length of 25,447 bp. It has a total GC content of 37.6% and encodes 132 genes, including 87 protein-coding genes, 37 tRNA genes, and eight rRNA genes. The phylogenetic relationships based on the complete chloroplast genome sequences of Hemiboea taxa indicate that H. pterocaulis is most closely related to H. suiyangensis, indicating that H. pterocaulis is an independent species and is separated from the H. subcapitata complex. These results provide valuable insights into the phylogeny, species divergence, and delimitation of the Hemiboea genus.

The complete chloroplast genome sequence of Myricaria wardii Marquand 1929 (Tamaricaceae): a shrub species endemic to the Tibet Plateau

Myricaria wardii Marquand 1929, endemic to the Tibet Plateau, is a perennial shrub with important medicinal and ecological values. In this study, the complete chloroplast (cp) genome of M. wardii was assembled, and the phylogenetic tree was reconstructed to evaluate the phylogenetic location of the species. The results showed that the cp genome size of the M. wardii was 155,299 bp, which contained a pair of inverted repeat (IR) regions (26,150 bp), a large single copy (LSC) region (84,715 bp), and a small single copy (SSC) region (18,284 bp). The total GC content of the cp genome was 36.30%. A total of 128 genes were annotated, consisting of 83 protein-coding genes, 37 tRNA genes and 8 rRNA genes. The phylogenetic analysis showed that M. wardii was closely related to M. prostrata. This study provides useful information for the conservation of this species and the phylogenetic analysis of Tamaricaceae.