Chloroplast Genome Data Research Articles

Comparative and Phylogenetic Analysis of Anthurium andraeanum Hybridization Based on Molecular and Morphological Traits

Hybridization is considered an important mode of species evolution, but the genetic evolutionary process of Anthurium andraeanum hybridization is still poorly characterized. In order to provide the molecular and morphological basis for phylogenetic analysis in A. andraeanum hybridization, we analyzed the morphological, nuclear genomic, and chloroplast genomic data of five A. andraeanum cultivars and explored the correlations between different traits and nuclear and chloroplast genome characteristics. A. andraeanum hybrid 1 is an A. andraeanum ‘Baron’ (♀) × A. andraeanum ‘Spice’ (♂) cross, and A. andraeanum hybrid 2 is an A. andraeanum ‘Cheers’ (♀) × A. andraeanum hybrid 1 (♂) cross. The A. andraeanum hybrids reflected their parents’ heterozygous features in their morphologies, nuclear genomes, and chloroplast genomes. The morphological traits in the F1 generation were widely separated, showing continuous variation. Based on cluster analysis, the five A. andraeanum cultivars could be divided into two groups. The ISSR analysis results were highly correlated with the spathe color. Among the five A. andraeanum cultivars, the composition and structure features of chloroplast genomes were completely the same or highly similar, respectively. Phylogenetic analysis based on complete chloroplast genome data showed that the genetic stability of the chloroplast is high in A. andraeanum, manifested as uniparental maternal inheritance, where the chloroplast genome composition and structural features of hybrids are highly similar to those of the maternal parent.

New insights on the phylogeny, evolutionary history, and ecological adaptation mechanism in cycle-cup oaks based on chloroplast genomes.

Cycle-cup oaks (Quercus section Cyclobalanopsis) are one of the principal components of forests in the tropical and subtropical climates of East and Southeast Asia. They have experienced relatively recent increases in the diversification rate, driven by changing climates and the Himalayan orogeny. However, the evolutionary history and adaptive mechanisms at the chloroplast genome level in cycle-cup oaks remain largely unknown. Therefore, we studied this problem by conducting chloroplast genomics on 50 of the ca. 90 species. Comparative genomics and other analyses showed that Quercus section Cyclobalanopsis had a highly conserved chloroplast genome structure. Highly divergent regions, such as the ndhF and ycf1 gene regions and the petN-psbM and rpoB-trnC-GCA intergenic spacer regions, provided potential molecular markers for subsequent analysis.The chloroplast phylogenomic tree indicated that Quercus section Cyclobalanopsis was not monophyletic, which mixed with the other two sections of subgenus Cerris. The reconstruction of ancestral aera inferred that Palaeotropics was the most likely ancestral range of Quercus section Cyclobalanopsis, and then dispersed to Sino-Japan and Sino-Himalaya. Positive selection analysis showed that the photosystem genes had the lowest ω values among the seven functional gene groups. And nine protein-coding genes containing sites for positive selection: ndhA, ndhD, ndhF, ndhH, rbcL, rpl32, accD, ycf1, and ycf2. This series of analyses together revealed the phylogeny, evolutionary history, and ecological adaptation mechanism of the chloroplast genome of Quercus section Cyclobalanopsis in the long river of earth history. These chloroplast genome data provide valuable information for deep insights into phylogenetic relationships and intraspecific diversity in Quercus.

Comparative analysis of 12 water lily plastid genomes reveals genomic divergence and evolutionary relationships in early flowering plants

The aquatic plant Nymphaea, a model genus of the early flowering plant lineage Nymphaeales and family Nymphaeaceae, has been extensively studied. However, the availability of chloroplast genome data for this genus is incomplete, and phylogenetic relationships within the order Nymphaeales remain controversial. In this study, 12 chloroplast genomes of Nymphaea were assembled and analyzed for the first time. These genomes were 158,290–160,042 bp in size and contained 113 non-repeat genes, including 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. We also report on codon usage, RNA editing sites, microsatellite structures, and new repetitive sequences in this genus. Comparative genomics revealed that expansion and contraction of IR regions can lead to changes in the gene numbers. Additionally, it was observed that the highly variable regions of the chloroplast genome were mainly located in intergenic regions. Furthermore, the phylogenetic tree showed the order Nymphaeales was divided into three families, and the genus Nymphaea can be divided into five (or three) subgenera, with the subgenus Nymphaea being the oldest. The divergence times of nymphaealean taxa were analyzed, with origins of the order Nymphaeales and family Nymphaeaceae being about 194 and 131 million years, respectively. The results of the phylogenetic analysis and estimated divergence times will be useful for future evolutionary studies of basal angiosperm lineages.

Decoding the Chloroplast Genome of Tetrastigma (Vitaceae): Variations and Phylogenetic Selection Insights.

Tetrastigma (Vitaceae) is known for its ornamental, medicinal, and ecological significance. However, the structural and variational characteristics of the Tetrastigma chloroplast genome and their impact on phylogenetic relationships remain underexplored. This study utilized bioinformatics methods to assemble and annotate the chloroplast genomes of 10 Tetrastigma species and compare them with five previously sequenced species. This study analyzed gene composition, simple sequence repeats, and codon usage patterns, revealing a high A/T content, uniquely identified pentanucleotide repeats in five species and several preferred codons. In addition, comparative analyses were conducted of the chloroplast genomes of 15 Tetrastigma species, examining their structural differences and identifying polymorphic hotspots (rps16, rps16-trnQ, trnS, trnD, psbC-trnS-psbZ, accD-psaI, psbE-petL-petG, etc.) suitable for DNA marker development. Furthermore, phylogenetic and selective pressure analyses were performed based on the chloroplast genomes of these 15 Tetrastigma species, validating and elucidating intra-genus relationships within Tetrastigma. Futhermore, several genes under positive selection, such as atpF and accD, were identified, shedding light on the adaptive evolution of Tetrastigma. Utilizing 40 Vitaceae species, the divergence time of Tetrastigma was estimated, clarifying the evolutionary relationships within Tetrastigma relative to other genera. The analysis revealed diverse divergences of Tetrastigma in the Miocene and Pliocene, with possible ancient divergence events before the Eocene. Furthermore, family-level selective pressure analysis identified key features distinguishing Tetrastigma from other genera, showing a higher degree of purifying selection. This research enriches the chloroplast genome data for Tetrastigma and offers new insights into species identification, phylogenetic analysis, and adaptive evolution, enhancing our understanding of the genetic diversity and evolutionary history of these species.

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 chloroplast genomes of two medicinal species (Veronica anagallis-aquatica L. and Veronica undulata Wall.) and its comparative analysis with related Veronica species

Veronica anagallis-aquatica L. and Veronica undulata Wall. are widely used ethnomedicinal plants in China. The two species have different clinical efficacies, while their extremely similar morphology and unclear interspecific relationship make it difficult to accurately identify them, leading to increased instances of mixed usage. This article reports on the complete chloroplast genomes sequence of these two species and their related Veronica species to conduct a comparative genomics analysis and phylogenetic construction. The results showed that the chloroplast (cp) genomes of Veronica exhibited typical circular quadripartite structures, with total lengths of 149,386 to 152,319 base pairs (bp), and GC content of 37.9 to 38.1%, and the number of genes was between 129–134. The total number of simple sequence repeats (SSRs) in V. anagallis-aquatica and V. undulata is 37 and 36, while V. arvensis had the highest total number of 56, predominantly characterized by A/T single bases. The vast majority of long repeat sequence types are forward repeats and palindromic repeats. Selective Ka/Ks values showed that three genes were under positive selection. Sequence differences often occur in the non-coding regions of the large single-copy region (LSC) and small single-copy region (SSC), with the lowest sequence variation in the inverted repeat regions (IR). Seven highly variable regions (trnT-GGU-psbD, rps8-rpl16, trnQ-UUG, trnN-GUU-ndhF, petL, ycf3, and ycf1) were detected, which may be potential molecular markers for identifying V. anagallis-aquatica and V. undulata. The phylogenetic tree indicates that there is a close genetic relationship between the genera Veronica and Neopicrorhiza, and V. anagallis-aquatica and V. undulata are sister groups. The molecular clock analysis results indicate that the divergence time of Veronica may occur at ∼ 9.09 Ma, and the divergence time of these two species occurs at ∼ 0.48 Ma. It is speculated that climate change may be the cause of Veronica species diversity and promote the radiation of the genus. The chloroplast genome data of nine Veronica specie provides important insights into the characteristics and evolution of the chloroplast genome of this genus, as well as the phylogenetic relationships of the genus Veronica.

TPMGD: A genomic database for the traditional medicines in Pakistan

ObjectiveIn Pakistan, traditional medicines are an important component of the medical system, with numerous varieties and great demands. However, due to the scattered resources and the lack of systematic collection and collation, adulteration of traditional Pakistani medicine (TPM) is common, which severely affects the safety of their medicinal use and the import and export trades. Therefore, it is urgent to systematically organize and unify the management of TPM and establish a set of standards and operable methods for the identification of TPM. MethodsWe collected and organized the information on 128 TPMs with regard to their medicinal parts, efficacy, usage, and genetic material, based on Pakistan Hamdard Pharmacopoeia of Eastern Medicine: Pharmaceutical Codex. The genetic information of TPM is summarized from national center for biotechnology information (NCBI) and global pharmacopoeia genome database (GPGD). Furthermore, we utilized bioinformatics technology to supplement the chloroplast genome (cp-genome) data of 12 TPMs. To build the web server, we used the Linux + Apache + MySQL + PHP (LAMP) system and constructed the webpage on a PHP: Hypertext Preprocessor (PHP) model view controller (MVC) framework. ResultsWe constructed a new genomic database, the traditional Pakistani medicine genomic database (TPMGD). This database comprises five entries, namely homepage, medicinal species, species identification, basic local alignment search tool (BLAST), and download. Currently, TPMGD contains basic profiles of 128 TPMs and genetic information of 102 TPMs, including 140 cytochrome c oxidase subunit I (COI) sequences and 119 mitochondrial genome sequences from Bombyx mori, 1 396 internal transcribed spacer 2 (ITS2) sequences and 1 074 intergenic region (psbA-trnH) sequences specific to 92 and 83 plant species, respectively. Additionally, TPMGD includes 199 cp-genome sequences of 82 TPMs. ConclusionTPMGD is a multifunctional database that integrates species description, functional information inquiry, genetic information storage, molecular identification of TPM, etc. The database not only provides convenience for TPM information queries but also establishes the scientific basis for the medication safety, species identification, and resource protection of TPM.

Phylogenetic and molecular dating analyses of Chinese endemic genus Dipelta (Caprifoliaceae) based on nuclear RAD‐Seq and chloroplast genome data

AbstractDipelta Maxim. (Caprifoliaceae) is a Tertiary relic genus endemic to China, which includes three extant species, Dipelta floribunda, Dipelta yunnanensis, and Dipelta elegans. Recent progress in the systematics and phylogeographics of Dipelta has greatly broadened our knowledge about its origin and evolution, however, conflicted phylogenetic relationships and divergence times have been reported and warrant further investigation. Here, we utilized chloroplast genomes and population‐level genomic data restriction site‐associated DNA‐single nucleotide polymorphisms (RAD‐SNPs) to evaluate the interspecific relationships, population genetic structure and demographic histories of this genus. Our results confirmed the sister relationship between D. elegans and the D. yunnanensis–D. floribunda group, but with cyto‐nuclear phylogenetic discordance observed in the latter. Coalescent simulations suggested that this discordance might be attributed to asymmetric “chloroplast capture” through introgressive hybridization between the two parapatric species. Our fossil‐calibrated plastid chronogram of Dipsacales and the coalescent modeling based on nuclear RAD‐SNPs simultaneously suggested that the three species of Dipelta diversified at the late Miocene, which may be related to the uplift of the eastern part of Qinghai–Tibet Plateau (QTP) and adjacent southwest China, and increasing Asian interior aridification since the late Miocene; while in the mid‐Pleistocene, the climatic transition and continuous uplift of the QTP, triggered allopatric speciation via geographical isolation for D. floribunda and D. yunnanensis regardless of bidirectional gene flow. Based on both plastid and nuclear genome‐scale data, our findings provide the most comprehensive and reliable phylogeny and evolutionary histories for Dipelta and enable further understanding of the origin and evolution of floristic endemisms of China.

Phylogeny of genera in Maleae (Rosaceae) based on chloroplast genome analysis.

In Rosaceae, the replacement of the traditional four-subfamily division (Amygdaloideae or Prunoideae, Maloideae, Rosoideae, and Spiraeoideae) by the three-subfamily division (Dryadoideae, Rosoideae, and Amygdaloideae), the circumscription, systematic position, and phylogeny of genera in Maleae need to be reconsidered. The study aimed to circumscribe Maleae, pinpoint its systematic position, and evaluate the status of all generally accepted genera in the tribe using complete chloroplast genome data. Results indicated that Maleae consisted of pome-bearing genera that belonged to Maloideae as well as four genera (Gillenia, Kageneckia, Lindleya, and Vauquelinia) that were formerly considered to be outside Maloideae. The tribe could be subdivided into four subtribes: Gilleniinae (Gillenia), Lindleyinae (Kageneckia and Lindleya), Vaugueliniinae (Vauquelinia), and Malinae (all other genera; the core Maleae). Among the 36 recognized genera, Aria, Docyniopsis, Chamaemespilus, and Mespilus were not considered distinct and more research is needed to determine the taxonomic status of Rhaphiolepis from Eriobotrya. Within the core Maleae, five groups were revealed, whereas Sorbus L. was split as its members belonged to different groups.

Hybridization, polyploidization, and morphological convergence make dozens of taxa into one chaotic genetic pool: a phylogenomic case of the Ficus erecta species complex (Moraceae).

The Ficus erecta complex, characterized by its morphological diversity and frequent interspecific overlap, shares pollinating fig wasps among several species. This attribute, coupled with its intricate phylogenetic relationships, establishes it as an exemplary model for studying speciation and evolutionary patterns. Extensive researches involving RADseq (Restriction-site associated DNA sequencing), complete chloroplast genome data, and flow cytometry methods were conducted, focusing on phylogenomic analysis, genetic structure, and ploidy detection within the complex. Significantly, the findings exposed a pronounced nuclear-cytoplasmic conflict. This evidence, together with genetic structure analysis, confirmed that hybridization within the complex is a frequent occurrence. The ploidy detection revealed widespread polyploidy, with certain species exhibiting multiple ploidy levels, including 2×, 3×, and 4×. Of particular note, only five species (F. abelii, F. erecta, F. formosana, F. tannoensis and F. vaccinioides) in the complex were proved to be monophyletic. Species such as F. gasparriniana, F. pandurata, and F. stenophylla were found to encompass multiple phylogenetically distinct lineages. This discovery, along with morphological comparisons, suggests a significant underestimation of species diversity within the complex. This study also identified F. tannoensis as an allopolyploid species originating from F. vaccinioide and F. erecta. Considering the integration of morphological, molecular systematics, and cytological evidences, it is proposed that the scope of the F. erecta complex should be expanded to the entire subsect. Frutescentiae. This would redefine the complex as a continuously evolving group comprising at least 33 taxa, characterized by blurred species boundaries, frequent hybridization and polyploidization, and ambiguous genetic differentiation.

Impacts of the attributes of patches and the surrounding matrix on the phylogenetic diversity of tree species in urban remnant forests

AbstractUrbanization is a major cause of biotic homogenization and evolutionary poverty. Urban remnant forests are biodiversity hotspots in cities but are prone to phylogenetic homogenization. However, how urbanization‐driven changes in patch attributes and landscape heterogeneity levels of the surrounding matrix affect plant phylogenetic diversity in urban remnant forests remains unclear. We quantified tree phylogenetic diversity and structure in 30 remnant forest patches in Guiyang, China, using chloroplast genome data and analyzed the effects of patch attributes and the surrounding matrix on tree phylogenetic diversity and structure in the forests while considering tree species stage. The phylogenetic diversity of saplings/seedlings was lower than that of adult trees. Small patches contributed more than large patches to the overall phylogenetic diversity of remnant forest ecosystems. Additionally, tree phylogenetic diversity was positively associated with configurational heterogeneity of the surrounding matrix, while phylogenetic diversity and relatedness were negatively related to the percentage of surrounding impervious surfaces and patch size. Accordingly, we suggest maintaining configurational heterogeneity and controlling the speed of urban expansion in the surrounding matrix to better conserve urban remnant forests. Furthermore, the preservation of small forest remnants and tree species in the sapling/seedling stage should be prioritized.

Characterization of the complete chloroplast genome of Wolffia arrhiza and comparative genomic analysis with relative Wolffia species

Lemnoideae, commonly referred to as the duckweed, are aquatic plants found worldwide. Wolffia species are known for their extreme reduction in size and complexity, lacking both roots and leaves, and they hold the distinction of being the smallest plants among angiosperms. Interestingly, it belongs to the Araceae family, despite its apparent morphological differences from land plants in the same family. Traditional morphological methods have limitations in classifying these plants, making molecular-level information essential. The chloroplast genome of Wolffia arrhiza is revealed that a total length of 169,602 bp and a total GC content of 35.78%. It follows the typical quadripartite structure, which includes a large single copy (LSC, 92,172 bp) region, a small single copy (SSC, 13,686 bp) region, and a pair of inverted repeat (IR, 31,872 bp each) regions. There are 131 genes characterized, comprising 86 Protein-Coding Genes, 37 Transfer RNA (tRNA) genes, and 8 ribosomal RNA (rRNA) genes. Moreover, 48 simple sequence repeats and 32 long repeat sequences were detected. Comparative analysis between W. arrhiza and six other Lemnoideae species identified 12 hotspots of high nucleotide diversity. In addition, a phylogenetic analysis was performed using 14 species belonging to the Araceae family and one external species as an outgroup. This analysis unveiled W. arrhiza and Wolffia globosa as closely related sister species. Therefore, this research has revealed the complete chloroplast genome data of W. arrhiza, offering a more detailed understanding of its evolutionary position and phylogenetic categorization within the Lemnoideae subfamily.

The complete chloroplast genome sequence of a cultivar of Chrysanthemum, Chrysanthemum × morifolium ‘Hangbaiju’ (Asteraceae)

Chrysanthemum × morifolium Ramat 1792 cultivar ‘Hangbaiju’, also known as ‘Hangzhou White Chrysanthemum’, originates from Tongxiang City, Zhejiang Province, China. It is celebrated as one of Zhejiang’s ‘eight flavors’. In this study, we reported the complete chloroplast genome of Chrysanthemum × morifolium cultivar ‘Hangbaiju’. The genome has a circular structure of 151,110 bp containing a large single-copy region (LSC) of 82,851 bp, a small copy region (SSC) of 18,351 bp, and two inverted repeats (IR) of 24,936 and 24,972 bp in length. It comprises 128 genes: 85 protein-coding gene, 8 ribosomal RNA (rRNA) genes, and 35 transfer RNA (tRNA) genes. Phylogenetic analysis, based on complete chloroplast genomes, demonstrates that Chrysanthemum × morifolium ‘Hangbaiju’ shares a close genetic cluster with Chrysanthemum × morifolium ‘Fubaiju’ (MT1919691.1). Notably, ‘Fubaiju’ was introduced to Macheng, Hubei Province from Tongxiang in 1968 according to public information. The chloroplast genome data, coupled with morphological and historical records, strongly suggest that they are the same variety known by different names based on their cultivation locations.

The identity of Bupleurum jeholense (Apiaceae)

Bupleurum jeholense Nakai (Apioideae, Apiaceae), originally found in the Wuling Mountain of China, was initially described as a species but later treated as a variety of B. sibiricum Vest ex Spreng. However, researchers have recently found that it is more closely related to B. chinense DC. In this study, we conducted morphological and phylogenetic analyses as well as chromosome counting to determine the taxonomic status of B. sibiricum var. jeholense (Nakai) Chu. Our results showed that B. sibiricum var. jeholense and B. chinense share common features (i.e., bracteoles 5 and stem solid) that distinguish both from B. sibiricum var. sibiricum. The chromosome number of B. sibiricum var. jeholense was found to be the same as in B. chinense (i.e., 2n = 12), whereas the chromosome number of B. sibiricum var. sibiricum was 64. A phylogenetic tree based on complete chloroplast genome data revealed a close relationship between B. sibiricum var. jeholense and B. chinense. Finally, B. sibiricum var. jeholense and B. chinense were mainly found to differ in plant height, number of stems, and middle stem leaves. Based on this evidence, we propose a new combination: Bupleurum chinense var. jeholense (Nakai) Q.R.Liu & L.H.Wang.

Plastid genomes provide insights into the phylogeny and chloroplast evolution of the paper daisy tribe Gnaphalieae (Asteraceae)

Chloroplast genomes, as an essential source of phylogenetic information, are increasingly utilized in the evolutionary study of angiosperms. Gnaphalieae is a medium-sized tribe of the sunflower family of Asteraceae, with about 2,100 species in 178 genera distributed in temperate habitats worldwide. There has been considerable progress in our understanding of their phylogenetic evolution using both nuclear and chloroplast sequences, but no focus on chloroplast genomic data. In this study, we performed sequencing, assembly, and annotation of 16 representative chloroplast genomes from all the major lineages of Gnaphalieae. Our results showed that the plastomes exhibited a typical circular tetrad structure with similar genomic structure gene content. But there were differences in genome size, SSRs, and codon usage within the tribe. Phylogenetic analysis revealed Relhania clade is the earliest diverged lineages with the Lasiopogon clade and the Gnaphalium s.s. clade diverged subsequently. The core group includes FLAG clade sister to the HAP and Australasian group. Compared with the outgroup species, chloroplast genome size of the FLAG clade is much reduced whereas those of Australasian, HAP, Gnaphalium s.s., Lasiopogon and Relhania clades are relatively expanded. Insertions and deletions in the intergenic regions associated with repetitive sequence variations are supposed to be the main factor leading to length variations in the chloroplast genomes of Gnaphalieae. The comparative analyses of chloroplast genomes would provide useful implications into understanding the taxonomic and evolutionary history of Gnaphalieae.

Reciprocal natural hybridization between Lycoris aurea and Lycoris radiata (Amaryllidaceae) identified by morphological, karyotypic and chloroplast genomic data

BackgroundHybridization is considered as an important model of speciation, but the evolutionary process of natural hybridization is still poorly characterized in Lycoris. To reveal the phylogenetic relationship of two new putative natural hybrids in Lycoris, morphological, karyotypic and chloroplast genomic data of four Lycoris species were analyzed in this study.ResultsTwo putative natural hybrids (2n = 18 = 4 m + 5t + 6st + 3 T) possessed obvious heterozygosity features of L. radiata (2n = 22 = 10t + 12st) and L. aurea (2n = 14 = 8 m + 6 T) in morphology (e.g. leaf shape and flower color), karyotype (e.g. chromosome numbers, CPD/DAPI bands, 45S rDNA-FISH signals etc.) and chloroplast genomes. Among four Lycoris species, the composition and structure features of chloroplast genomes between L. radiata and the putative natural hybrid 1 (L. hunanensis), while L. aurea and the hybrid 2, were completely the same or highly similar, respectively. However, the features of the cp genomes between L. radiata and the hybrid 2, while L. aurea and the hybrid 1, including IR-LSC/SSC boundaries, SSRs, SNPs, and SNVs etc., were significantly different, respectively. Combining the karyotypes and cp genomes analysis, we affirmed that the natural hybrid 1 originated from the natural hybridization of L. radiata (♀) × L. aurea (♂), while the natural hybrid 2 from the hybridization of L. radiata (♂) × L. aurea (♀).ConclusionThe strong evidences for natural hybridization between L. radiata (2n = 22) and L. aurea (2n = 14) were found based on morphological, karyotypic and chloroplast genomic data. Their reciprocal hybridization gave rise to two new taxa (2n = 18) of Lycoris. This study revealed the origin of two new species of Lycoris and strongly supported the role of natural hybridization that facilitated lineage diversification in this genus.

Characterization and phylogenetic analysis of the complete chloroplast genome of Asterothamnus centraliasiaticus Novopokr. (Asteraceae: Asterothamnus)

Asterothamnus centraliasiaticus Novopokr., a species of perennial deciduous semi-shrub within the family Asteraceae, has excellent medical, economic, ecological and genetic value. In this study, the chloroplast genome of A. centraliasiaticus was first assembled using Illumina HiSeq2500 sequences. The results indicate that the complete cp genome of A. centraliasiaticus is 152,205 bp in length, and comprises a pair of inverted repeat (IR) regions of 25,031 bp each, a large single-copy (LSC) region of 83,956 bp and a small single-copy (SSC) region of 18,187 bp. The GC content of A. centraliasiaticus is 37.3%. A total of 130 genes were successfully annotated containing 85 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The maximum likelihood (ML) phylogenetic analysis based on the complete chloroplast genome data highly supported that A. centraliasiaticus was close to Aster lavandulifolius. These results will provide significant genetic information for the germplasm protection and reasonable development.

Characterization and phylogenetic analysis of complete chloroplast genome of cultivated Qinan agarwood

"Tangjie" leaves of cultivated Qinan agarwood were used to obtain the complete chloroplast genome using high-throughput sequencing technology. Combined with 12 chloroplast genomes of Aquilaria species downloaded from NCBI, bioinformatics method was employed to determine the chloroplast genome characteristics and phylogenetic relationships. The results showed that the chloroplast genome sequence length of cultivated Qinan agarwood "Tangjie" leaves was 174 909 bp with a GC content of 36.7%. A total of 136 genes were annotated, including 90 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. Sequence repeat analysis detected 80 simple sequence repeats(SSRs) and 124 long sequence repeats, with most SSRs composed of A and T bases. Codon preference analysis revealed that AUU was the most frequently used codon, and codons with A and U endings were preferred. Comparative analysis of Aquilaria chloroplast genomes showed relative conservation of the IR region boundaries and identified five highly variable regions: trnD-trnY, trnT-trnL, trnF-ndhJ, petA-cemA, and rpl32, which could serve as potential DNA barcodes specific to the Aquilaria genus. Selection pressure analysis indicated positive selection in the rbcL, rps11, and rpl32 genes. Phylogenetic analysis revealed that cultivated Qinan agarwood "Tangjie" and Aquilaria agallocha clustered together(100% support), supporting the Chinese origin of Qinan agarwood from Aquilaria agallocha. The chloroplast genome data obtained in this study provide a foundation for studying the genetic diversity of cultivated Qinan agarwood and molecular identification of the Aquilaria genus.

Insights into phylogenetic relationships in Pinus inferred from a comparative analysis of complete chloroplast genomes

BackgroundPinus is the largest genus of Pinaceae and the most primitive group of modern genera. Pines have become the focus of many molecular evolution studies because of their wide use and ecological significance. However, due to the lack of complete chloroplast genome data, the evolutionary relationship and classification of pines are still controversial. With the development of new generation sequencing technology, sequence data of pines are becoming abundant. Here, we systematically analyzed and summarized the chloroplast genomes of 33 published pine species.ResultsGenerally, pines chloroplast genome structure showed strong conservation and high similarity. The chloroplast genome length ranged from 114,082 to 121,530 bp with similar positions and arrangements of all genes, while the GC content ranged from 38.45 to 39.00%. Reverse repeats showed a shrinking evolutionary trend, with IRa/IRb length ranging from 267 to 495 bp. A total of 3,205 microsatellite sequences and 5,436 repeats were detected in the studied species chloroplasts. Additionally, two hypervariable regions were assessed, providing potential molecular markers for future phylogenetic studies and population genetics. Through the phylogenetic analysis of complete chloroplast genomes, we offered novel opinions on the genus traditional evolutionary theory and classification.ConclusionWe compared and analyzed the chloroplast genomes of 33 pine species, verified the traditional evolutionary theory and classification, and reclassified some controversial species classification. This study is helpful in analyzing the evolution, genetic structure, and the development of chloroplast DNA markers in Pinus.

Pueraria montana Population Structure and Genetic Diversity Based on Chloroplast Genome Data.

Despite having a generally conserved structure, chloroplast genome data have been helpful for plant population genetics and evolution research. To mine Pueraria montana chloroplast genome variation architecture and phylogeny, we investigated the chloroplast variation architecture of 104 P. montana accessions from across China. P. montana's chloroplast genome showed high diversity levels, with 1674 variations, including 1118 single nucleotide polymorphisms and 556 indels. The intergenic spacers, psbZ-trnS and ccsA-ndhD, are the two mutation hotspot regions in the P. montana chloroplast genome. Phylogenetic analysis based on the chloroplast genome dataset supported four P. montana clades. P. montana variations were conserved among and within clades, which showed high gene flow levels. Most P. montana clades were estimated to have diverged at 3.82-5.17 million years ago. Moreover, the East Asian summer monsoon and South Asian summer monsoon may have accelerated population divergence. Our results show that chloroplast genome sequences were highly variable and can be used as molecular markers to assess genetic variation and relationships in P. montana.