Large Single-copy Region Research Articles

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.

The complete plastome and phylogenetic analysis of Commelina benghalensis L.1753 (Commelinaceae)

Commelina benghalensis L. 1753, a member of the Commelinaceae family, holds significant medicinal and culinary value. This study represents the first documentation of the sequencing and assembly of the entire plastome of C. benghalensis. The genome spans a total length of 160,663 bp, exhibiting a conventional quadripartite architecture that comprises a large single-copy (LSC) region (87,750 bp), a small single-copy (SSC) region (18,417 bp), and two inverted repeats (IR) regions (both 27,248 bp). In its entirety, the C. benghalensis plastome encompasses 129 genes (with 108 being unique), incorporating 77 individual protein-coding genes, 37 unique tRNA genes, and four unique rRNA genes. Phylogenetic analysis revealed a close resemblance between C. benghalensis and C. communis. The sequencing of this plastome stands to expedite the development of molecular markers and significantly contribute to genetic assays involving this distinctive plant.

The complete chloroplast genome assembly of Amorphophallus tonkinensis Engler and Gehrmann 1911 from southwestern China

Species in the Amorphophallus genus are important cash crops in many tropical and subtropical Asian countries. Although several molecular markers have been employed to determine relationships and assess genetic variation in the Amorphophallus genus, some conflicts remain in infrageneric classification and evolution. To aid in the phylogenetic research of the Amorphophallus genus, we collected one sample of Amorphophallus tonkinensis Engler and Gehrmann 1911 from southwestern China. We assembled the first chloroplast genome of this species using high-throughput sequencing. The assembled genome was 169,341 bp long with a typical quadripartite structure (GenBank accession number: PP234804). The lengths of the large single-copy region, small single-copy region, and two inverted repeats were 90,705 bp, 15,640 bp, 31,498 bp, and 31,498 bp, respectively. We annotated 129 genes across the chloroplast genome of A. tonkinensis. The phylogenetic trees suggested that the Amorphophallus species distributed in continental Asia split into two main clades. The chloroplast genome reported in our study provided valuable genomic resources for the future phylogenetic research of the Amorphophallus genus.

Comparative analysis of sipeimine content, metabolome and chloroplast genome in cultivated and wild varieties of Fritillaria taipaiensis.

The wild variety Fritillaria taipaiensis E.B (EB) is known for its superior therapeutic effects, but its limited production cannot meet demand. As a result, the cultivated variety F. taipaiensis P. Y. Li (PY) has been widely grown. In this study, we conducted a comprehensive analysis comparing EB and PY in terms of external features, sipeimine content, metabolome and chloroplast genome to differentiate these two varieties. Our research revealed that the petals and pods of EB are green, while those of PY have purple markings. The bulbs of EB contain significantly higher levels of sipeimine compared to those of PY. Metabolomic analysis identified 56 differentially expressed metabolites (DMs), with 23 upregulated and 33 downregulated in EB bulbs. Particularly, 3-hydroxycinnamic acid and secoxyloganin may serve as distinctive DMs. These DMs were associated with 17 KEGG pathways, including pyrimidine metabolism, alanine, aspartate and glutamate metabolism, and galactose metabolism. Differences in the length of the chloroplast genome were primarily observed in the large single-copy (LSC) region, with the largest variation in the trnH-GUC-psbA region. The placement of the trnH gene and the rps gene in proximity to the LSC/IRb boundary differs between EB and PY. The results of this study provide valuable insights for the introduction and comprehensive development of wild F. taipaiensis from a scientific perspective. © 2024 Society of Chemical Industry.

The complete chloroplast genome sequence of leibnitzia anandria (linnaeus) turczaninow

Leibnitzia anandria is a perennial herbaceous plant with medicinal properties, and the entire plant can be used in traditional medicine. Leibnitzia anandria was once classified under the genus Gerbera Cass., but was reclassified under Leibnitzia Cass. recently. In this study, using the GeneLab M sequencing technology of the Genemind platform, we have sequenced, assembled, and analyzed the complete chloroplast genome of Leibnitzia anandria for the first time. The genome is 154168 bp in length, consisting of a large single-copy region(LSC, 80166 bp), a small single-copy region(SSC, 18202 bp), and a pair of inverted repeat sequences(IR, 27900 bp). We have predicted and annotated a total of 133 genes, including 88 protein-coding genes, 37 tRNA-coding genes, and 8 rRNA-coding genes. The results of the phylogenetic analysis indicate that Leibnitzia anandria and Leibnitzia nepalensis, as well as the closely related Gerbera plant, clustered into a separate clade, rather than grouping together with the other plants belonging to the tribe Mutisieae. This study provides new information for the phylogeny research of Leibnitzia anandria, contributing to a better understanding of its taxonomy and evolution.

Insights into chloroplast genome evolution in Rutaceae through population genomics

Chloroplast genomes, pivotal for understanding plant evolution, remain unexplored in Rutaceae, a family with key perennial crops like citrus. Leveraging next-generation sequencing data from 509 Rutaceae accessions across 15 species, we conducted a de novo assembly of 343 chloroplast genomes, unveiling a chloroplast variation map highlighting the heterogeneous evolution rates across genome regions. Notably, differences in chloroplast genome size primarily originate from large single-copy and small single-copy regions. Structural variants predominantly occurred in the single-copy region, with two insertions located at the single-copy and inverted repeat region boundary. Phylogenetic analysis, principal component analysis, and population genetic statistics confirmed the cohesive clustering of different Citrus species, reflecting evolutionary dynamics in Citrus diversification. Furthermore, a close chloroplast genetic affinity was revealed among Atalantia (previously regarded as primitive citrus), Clausena, and Murraya. Zanthoxylum formed a distinct group with heightened genetic diversity. Through expanding our analysis to include 34 published chloroplast genomes, we explored chloroplast gene selection, revealing divergent evolutionary trends in photosynthetic pathways. While Photosystem I and Photosystem II exhibited robust negative selection, indicating stability, the Nicotinamide adenine dinucleotide (NADH) dehydrogenase pathway demonstrated rapid evolution, which was indicative of environmental adaptation. Finally, we discussed the effects of gene length and GC content on chloroplast gene evolution. In conclusion, our study reveals the genetic characterization of chloroplast genomes during Rutaceae diversification, providing insights into the evolutionary history of this family.

The first complete chloroplast genome of Thalictrum fargesii: insights into phylogeny and species identification.

Thalictrum fargesii is a medicinal plant belonging to the genus Thalictrum of the Ranunculaceae family and has been used in herbal medicine in the Himalayan regions of China and India. This species is taxonomically challenging because of its morphological similarities to other species within the genus. Thus, herbal drugs from this species are frequently adulterated, substituted, or mixed with other species, thereby endangering consumer safety. The present study aimed to sequence and assemble the entire chloroplast (cp) genome of T. fargesii using the Illumina HiSeq 2500 platform to better understand the genomic architecture, gene composition, and phylogenetic relationships within the Thalictrum. The cp genome was 155,929 bp long and contained large single-copy (85,395 bp) and small single-copy (17,576 bp) regions that were segregated by a pair of inverted repeat regions (26,479 bp) to form a quadripartite structure. The cp genome contains 133 genes, including 88 protein-coding genes (PCGs), 37 tRNA genes, and 8 rRNA genes. Additionally, this genome contains 64 codons that encode 20 amino acids, the most preferred of which are alanine and leucine. We identified 68 SSRs, 27 long repeats, and 242 high-confidence C-to-U RNA-editing sites in the cp genome. Moreover, we discovered seven divergent hotspot regions in the cp genome of T. fargesii, among which ndhD-psaC and rpl16-rps3 may be useful for developing molecular markers for identifying ethnodrug species and their contaminants. A comparative study with eight other species in the genus revealed that pafI and rps19 had highly variable sites in the cp genome of T.fargesii. Additionally, two special features, (i) the shortest length of the ycf1 gene at the IRA-SSC boundary and (ii) the distance between the rps19 fragment and trnH at the IRA-LSC junction, distinguish the cp genome of T. fargesii from those of other species within the genus. Furthermore, phylogenetic analysis revealed that T. fargesii was closely related to T. tenue and T. petaloidium. Considering all these lines of evidence, our findings offer crucial molecular and evolutionary information that could play a significant role in further species identification, evolution, and phylogenetic studies on T. fargesii.

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.

Solanum aculeatissimum and Solanum torvum chloroplast genome sequences: a comparative analysis with other Solanum chloroplast genomes

BackgroundSolanum aculeatissimum and Solanum torvum belong to the Solanum species, and they are essential plants known for their high resistance to diseases and adverse conditions. They are frequently used as rootstocks for grafting and are often crossbred with other Solanum species to leverage their resistance traits. However, the phylogenetic relationship between S. aculeatissimum and S. torvum within the Solanum genus remains unclear. Therefore, this paper aims to sequence the complete chloroplast genomes of S. aculeatissimum and S. torvum and analyze them in comparison with 29 other previously published chloroplast genomes of Solanum species.ResultsWe observed that the chloroplast genomes of S. aculeatissimum and S. torvum possess typical tetrameric structures, consisting of one Large Single Copy (LSC) region, two reverse-symmetric Inverted Repeats (IRs), and one Small Single Copy (SSC) region. The total length of these chloroplast genomes ranged from 154,942 to 156,004 bp, with minimal variation. The highest GC content was found in the IR region, while the lowest was in the SSC region. Regarding gene content, the total number of chloroplast genes and CDS genes remained relatively consistent, ranging from 128 to 134 and 83 to 91, respectively. Nevertheless, there was notable variability in the number of tRNA genes and rRNAs. Relative synonymous codon usage (RSCU) analysis revealed that both S. aculeatissimum and S. torvum preferred codons that utilized A and U bases. Analysis of the IR boundary regions indicated that contraction and expansion primarily occurred at the junction between SSC and IR regions. Nucleotide polymorphism analysis and structural variation analysis demonstrated that chloroplast variation in Solanum species mainly occurred in the LSC and SSC regions. Repeat sequence analysis revealed that A/T was the most frequent base pair in simple repeat sequences (SSR), while Palindromic and Forward repeats were more common in long sequence repeats (LSR), with Reverse and Complement repeats being less frequent. Phylogenetic analysis indicated that S. aculeatissimum and S. torvum belonged to the same meristem and were more closely related to Cultivated Eggplant.ConclusionThese findings enhance our comprehension of chloroplast genomes within the Solanum genus, offering valuable insights for plant classification, evolutionary studies, and potential molecular markers for species identification.

Complete Chloroplast Genome of Alternanthera sessilis and Comparative Analysis with Its Congeneric Invasive Weed Alternanthera philoxeroides

Alternanthera sessilis is considered the closest relative to the invasive weed Alternanthera philoxeroides in China, making it an important native species for studying the invasive mechanisms and adaptations of A. philoxeroides. Chloroplasts play a crucial role in a plant’s environmental adaptation, with their genomes being pivotal in the evolution and adaptation of both invasive and related species. However, the chloroplast genome of A. sessilis has remained unknown until now. In this study, we sequenced and assembled the complete chloroplast genome of A. sessilis using high-throughput sequencing. The A. sessilis chloroplast genome is 151,935 base pairs long, comprising two inverted repeat regions, a large single copy region, and a small single copy region. This chloroplast genome contains 128 genes, including 8 rRNA-coding genes, 37 tRNA-coding genes, 4 pseudogenes, and 83 protein-coding genes. When compared to the chloroplast genome of the invasive weed A. philoxeroides and other Amaranthaceae species, we observed significant variations in the ccsA, ycf1, and ycf2 regions in the A. sessilis chloroplast genome. Moreover, two genes, ccsA and accD, were found to be undergoing rapid evolution due to positive selection pressure. The phylogenetic trees were constructed for the Amaranthaceae family, estimating the time of independent species formation between A. philoxeroides and A. sessilis to be approximately 3.5186–8.8242 million years ago. These findings provide a foundation for understanding the population variation within invasive species among the Alternanthera genus.

The complete chloroplast genome of Mussaenda pubescens and phylogenetic analysis

The chloroplast (cp) genome sequence of Mussaenda pubescens, a promising resource that is used as a traditional medicine and drink, is important for understanding the phylogenetic relationships among the Mussaenda family and genetic improvement and reservation. This research represented the first comprehensive description of the morphological characteristics of M. pubescens, as well as an analysis of the complete cp genome and phylogenetic relationship. The results indicated a close relationship between M. pubescens and M. hirsutula based on the morphological characteristics of the flower and leaves. The cp was sequenced using the Illumina NovaSeq 6000 platform. The results indicated the cp genome of M. pubescens spanned a total length of 155,122 bp, including a pair of inverted repeats (IRA and IRB) with a length of 25,871 bp for each region, as well as a large single-copy (LSC) region and a small single-copy (SSC) region with lengths of 85,370 bp and 18,010 bp, respectively. The results of phylogenetic analyses demonstrated that species within the same genus displayed a tendency to group closely together. It was suggested that Antirhea, Cinchona, Mitragyna, Neolamarckia, and Uncaria might have experienced an early divergence. Furthermore, M. hirsutula showed a close genetic connection to M. pubescens, with the two species having partially overlapping distributions in China. This study presents crucial findings regarding the identification, evolution, and phylogenetic research on Mussaenda plants, specifically targeting M. pubescens.

The complete chloroplast genome assembly of Commelina caroliniana Walter (Commelinaceae)

We sequenced and published the chloroplast genome of Commelina caroliniana Walter, which was previously misidentified as C. diffusa owing to their morphological similarities until 1989. The genome of C. caroliniana is 160,857 bp long [large single copy region: 88,064 bp; a small single copy region: 18,549 bp; two inverted repeat regions: 27,122 bp] and has a GC content of 35.7%. The genome comprises 133 genes, including 87 coding sequences (CDSs), 38 tRNAs, and eight rRNAs. The phylogenetic relationship between C. caroliniana and related species was analyzed using the maximum likelihood method based on the 79 CDSs of the chloroplast genome. Phylogenetic analysis revealed that C. caroliniana is closely related to C. communis. Our findings will contribute to studies on species identification and phylogenetic and evolutionary research. These results enhance our understanding of the Commelina genus.

Characterization of the complete chloroplast genome sequence of Camellia tetracocca (Theaceae)

Camellia tetracocca H.T. Chang 1981 is an important wild relative of cultivated tea plants. Its leaves are widely used by local people to make tea, showing great economic and breeding values. We here report the complete chloroplast genome of C. tetracocca using Illumina sequencing technology. The complete chloroplast genome of C. tetracocca is 157,026 bp in length, and structurally contains a pair of inverted repeat regions (IRa and IRb, 26,052 bp) separated by a large single-copy region (LSC, 86,669 bp) and a small single-copy region (SSC, 18,253 bp). It is composed of 131 predicted genes, including 86 protein-coding genes, 37 transfer RNA genes, and eight ribosomal RNA genes. The overall GC content is 37.31%. Phylogenetic analysis among four Camellia species and 11 other close species reveals a close relationship between C. tetracocca and C. gymnogyna.

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.

The complete chloroplast genome sequence of Rhamnella wilsonii Schneid (Rhamnaceae)

Rhamnella wilsonii Schneid 1914 is a member of the Rhamnaceae and endemic to China. In this study, the complete chloroplast genome of R. wilsonii was sequenced and assembled. The complete chloroplast genome was 160,049 bp in length, including a pair of inverted repeats (IRs) of 26,502 bp, one large single copy (LSC) region of 88,274 bp and one small single copy (SSC) region of 18,771 bp. The genome contained 129 genes, including 8 rRNA genes, 37 tRNA genes and 84 protein-coding genes. The overall GC content of the complete chloroplast genome was 37.15%. The phylogenetic analysis demonstrated that R. wilsonii is closely related to R. martinni. This study provides basic information for further studies on the identification and evolution of R. wilsonii and Rhamnella from genomic perspective.

Characterization of the complete chloroplast genome of Eutrema deltoideum (Brassicaceae)

Eutrema deltoideum (Hook. f. et Thoms.) has been recognized as a potentially important vegetable and medicinal resource. In this study, we present the complete chloroplast genome of E. deltoideum and conduct a phylogenetic analysis. The chloroplast genome is 154,051 bp long and consists of a large single-copy (LSC) region of 84,149 bp, two inverted repeat (IR) regions of 26,065 bp each, and a small single-copy (SSC) region of 17,772 bp. It contains 132 complete genes, including 87 protein-coding genes, 8 ribosomal RNA genes, and 37 tRNA genes. Additionally, we identified 78 simple sequence repeats (SSRs). The phylogenetic tree reveals that E. deltoideum is closely related to E. heterophyllum, and the Eutrema genus is monophyletic. This study provides valuable information about E. deltoideum and enhances our understanding of its taxonomic classification.

The complete chloroplast genome of Lagochilus ilicifolius Bunge ex Bentham, Labiat. Gen. 1834 (Lamiaceae) and its phylogenetic analysis

Lagochilus ilicifolius Bunge ex Bentham, Labiat. Gen is a perennial herb with much-branched stems native to Nei Mongol, Ningxia, Gansu, N Shaanxi. It can be used clinically as a hemostatic agent. The chloroplast genome length is 151,466 bp. It contained two inverted repeat regions of 25,660 bp each, a large single-copy region of length 82,504 bp, and a small single-copy region of length 17,642 bp. Also, the GC content is 38.6%. There were 133 genes annotated, including 88 known protein-coding genes, 37 tRNAs, and eight rRNAs. The phylogenetic tree was constructed using Bayesian method for plastome data of 29 species. The entire chloroplast genome of L. ilicifolius within the Lamiaceae is the first to reveal genetic taxonomy at the molecular level, and the new phylogenetic tree data can be used for future evolutionary studies.

The complete chloroplast genome assembly of Amorphophallus kiusianus makino 1913 (araceae) from Southern China

The mountainous region of southern China has been characterized by its complicated environment and topography. Amorphophallus kiusianus Makino 1913 is a representative species of extreme habitat preference that resides mainly in this region. To help study the genetic differentiation mechanisms of A. kiusianus populations, we sequenced the first chloroplast genome of this species using next-generation sequencing. The chloroplast genome was 166,269 bp in length with an average GC content of 36% (GenBank accession number: PP072243). The lengths of the large single-copy region (LSC), small single-copy region (SSC), and two inverted repeats (IRs) were 90,701 bp, 14,802 bp, 31,383 bp, and 31,383 bp, respectively. One hundred and twenty-nine genes were annotated in the chloroplast genome, including 84 protein-coding genes, 8 rRNA genes, and 37 tRNA genes. The phylogenetic tree suggested a close relationship among A. kiusianus, A. yunnanensis, and A. coaetaneus. The chloroplast genome reported in this study provides valuable genomic resources for the future phylogeographic research of A. kiusianus.

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.

Characterization of the complete chloroplast genome sequence of Agave durangensis (Asparagales: Asparagaceae: Agavoideae)

Agave durangensis commonly known as agave cenizo, is an endemic Agave species in Mexico used for mescal production, yet its taxonomic delimitation is still controversial. This study aimed to enhance taxonomic clarity by characterizing its chloroplast genome. Chloroplast DNA was isolated from 2-year-old A. durangensis leaves. The complete chloroplast genome size was 156,441 bp, comprising a large single-copy region (LSC), a pair of inverted repeat regions (IR), and a small single-copy region (SSC). Annotation revealed 87 protein-coding genes, 38 tRNAs, and 8 rRNAs, with notable gene inversions. Phylogenetic analysis suggests, A. durangensis forms a separate lineage within the Agave genus.