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Introduction: This study presents the first complete plastome (cpDNA) sequence of Psydrax latifolia, a member of the Rubiaceae family, which includes small trees, smooth shrubs, and occasionally lianas. This specimen was collected near the Red Sea coast in Jazan province, Saudi Arabia, specifically in the paleotropical Fifa Mountains. The research aimed to characterize and compare the plastome of Psydrax latifolia with other species in the Rubiaceae family to enhance our understanding of its evolutionary dynamics and phylogenetic relationships. Methods: The plastome of P. latifolia was sequenced and reconstructed using whole-genome next-generation sequencing (NGS) techniques. Comparative analyses were performed between the plastome of P. latifolia and 16 other species within the Rubiaceae family to identify genomic features and evolutionary patterns. The plastome structure, gene content, and codon usage were analyzed, with a focus on the Relative Synonymous Codon Usage (RSCU) in different regions of the plastome. Results: The plastome of P. latifolia was found to be 153,242 base pairs (bp) in length, including a large single copy (LSC) region of 83,603 bp, a small single copy (SSC) region of 18,115 bp, and a pair of inverted repeats (IRs) of 25,762 bp each. It contained 87 protein-coding genes, 8 rRNA genes, and 33 tRNA genes, with an overall GC content of 37.30%. The RSCU analysis revealed regional variation, with the protein-coding region being more conserved than the intergenic spacer. Discussion: This study provides the first complete plastome sequence of Psydrax latifolia, offering insights into its genomic structure and phylogenetic position within the Rubiaceae family. Comparative analyses with 16 Rubiaceae species highlighted distinct genomic features and evolutionary patterns. These findings contribute to the understanding of plastome evolution in the Rubiaceae family and provide a valuable resource for future phylogenetic and evolutionary studies. [ABSTRACT FROM AUTHOR]

The succulent shrubs Desmidorchis penicillata and D. retrospiciens, part of the taxonomically challenging genus Desmidorchis, are well‐known for their ecological resilience and medicinal significance. This study sequences the first complete chloroplast genomes of these species, shedding light on their genomic characteristics and evolutionary relationships. The circular genomes of D. penicillata (161 776 bp) and D. retrospiciens (162 277 bp) display a quadripartite structure typical of Angiosperms. Gene content, order, and GC content are consistent, featuring 114 unique genes, including 80 protein‐coding, 30 transfer RNAs, and four ribosomal RNAs genes. Codon usage analysis underscores A/U‐rich preferences, while RNA editing sites, predominantly in ndhB and ndhD genes, suggest post‐transcriptional modifications. Analysis of long repeated sequences reveals a predominance of forward and palindromic repeats. Simple sequence repeats (SSRs), particularly A/T motifs, are abundant, with high presence of mononucleotide, offering potential molecular markers. Comparative analysis with their relatives in subtribe Stapeliinae identifies mutational hotspots such as ycf1, ndhF, trnG(GCC)‐trnfM(CGA) and ndhG‐ndhI that could be potential DNA barcoding markers. The inverted repeat (IR) boundaries analysis revealed an expansion of IR on the small single copy region, leading to the formation of a pseudogene. Overall, substitution rate analysis indicated purifying selection, with a few genes (rpl22, clpP and rps11) showing signatures of positive selection. Additionally, the phylogenetic analysis positioned Desmidorchis within the Stapeliinae clade and strongly supported the sister relationship between D. penicillata and D. retrospiciens. This study provides comprehensive molecular data for future research in Desmidorchis. [ABSTRACT FROM AUTHOR]

In land plants, plastids acquired different functions and structures in parallel with the increasing genetic, developmental, and morphological diversity attained by the plant tissues. There are transition dynamics among the morpho-functional features of the different plastid types. This review is focused on plastid structure and interconversion with a focus on recent findings and a special attention to plastid types that are less known than chloroplasts. The morpho-physiological and biochemical differences, which explain the multiple functions of each plastid type and the transcriptional and post-translational modulation of plastid capabilities are here described. The structural dynamism of plastids is also discussed through their ability to produce protrusions called stromules and the activity of lipoprotein particles known as plastoglobules. As a consequence of the proteome differences among plastid types, the conversion from one type of plastid to another requires an organellar proteome reorganization with a turnover of plastid proteins, but also a differentially regulated import of nuclear-encoded proteins. Plastid degradation by macroautophagy and microautophagy pathways is also described. Taken together, all this information allows us to interpret plastids as sensors in development and plastid interconversion as a way that the plant uses to modify its growth. [ABSTRACT FROM AUTHOR]

Ongoing climate change has had severe impacts on biota worldwide, including plants and especially those with narrow ecological niches that have adapted to extreme environments for several hundred thousand of years. Several members of the genus Tillandsia are known for their ability to live at the dry limits of life in the Atacama Desert and have potential as bioindicators for climate change at the Pacific Ocean and adjacent ecosystems. However, genomic information on these plants is scarce. In this study, five complete plastid genomes of two Tillandsia species were de novo assembled at very high quality using DNA sequence data from a combination of next-generation short-read and Sanger sequencing. The newly assembled and fully annotated plastid genomes had an average length of 156,319 base-pairs with the typical highly conserved quadripartite circular structures. Gene order and content were highly conserved, with the exception of the variable gene ycf1. The newly assembled plastid genomes were placed into a broader phylogenetic context to check the quality of sequence data obtained from past approaches relying on reference-based assemblies. It is shown that earlier presented Tillandsia plastomes are either not of sufficient quality or lack any metadata. The herein presented reference plastomes will guide future research to study parallel and convergent evolution in a reliable evolutionary framework and will allow the use of plastome data with little genetic variation for population genomics studies in species such as Tillandisa landbeckii with prevailing clonal propagation. [ABSTRACT FROM AUTHOR]

The genus Pourthiaea Decne., a deciduous woody group with high ornamental value, belongs to the family Rosaceae. Here, we reported newly sequenced plastid genome sequences of Pourthiaea beauverdiana (C. K. Schneid.) Hatus., Pourthiaea parvifolia E. Pritz., Pourthiaea villosa (Thunb.) Decne., and Photinia glomerata Rehder & E. H. Wilson. The plastomes of these three Pourthiaea species shared the typical quadripartite structures, ranging in size from 159,903 bp (P. parvifolia) to 160,090 bp (P. beauverdiana). The three Pourthiaea plastomes contained a pair of inverted repeat regions (26,394–26,399 bp), separated by a small single-copy region (19,304–19,322 bp) and a large single-copy region (87,811–87,973 bp). A total of 113 unique genes were predicted for the three Pourthiaea plastomes, including four ribosomal RNA genes, 30 transfer RNA genes, and 79 protein-coding genes. Analyses of inverted repeat/single-copy boundary, mVISTA, nucleotide diversity, and genetic distance showed that the plastomes of 13 Pourthiaea species (including 10 published plastomes) are highly conserved. The number of simple sequence repeats and long repeat sequences is similar among 13 Pourthiaea species. The three non-coding regions (trnT-GGU-psbD, trnR-UCU-atpA, and trnH-GUG-psbA) were the most divergent. Only one plastid protein-coding gene, rbcL, was under positive selection. Phylogenetic analyses based on 78 shared plastid protein-coding sequences and 29 nrDNA sequences strongly supported the monophyly of Pourthiaea. As for the relationship with other genera in our phylogenies, Pourthiaea was sister to Malus in plastome phylogenies, while it was sister to the remaining genera in nrDNA phylogenies. Furthermore, significant cytonuclear discordance likely stems from hybridization events within Pourthiaea, reflecting complex evolutionary dynamics within the genus. Our study provides valuable genetic insights for further phylogenetic, taxonomic, and species delimitation studies in Pourthiaea, as well as essential support for horticultural improvement and conservation of the germplasm resources. [ABSTRACT FROM AUTHOR]

Plantago (plantains, Plantaginaceae) is a cosmopolitan genus including over 250 species used as functional foods, forage, and traditional medicine. Among them, Plantago lanceolata is commonly used as an ingredient of herbal products, but the close similarity to other Plantago species can cause misidentifications with potentially serious consequences for product safety/quality. To test the possibility of developing species-specific barcoding markers, we de novo assembled plastome sequences of individuals of Plantago argentea, Plantago atrata, P. lanceolata, and Plantago maritima. These genomes were characterized in comparison with both previously sequenced conspecific accessions and other publicly available plastomes, thus providing an assessment of both intraspecific and interspecific genetic variation in Plantago plastomes. Additionally, molecular evolutionary analyses indicated that eleven protein-coding genes involved in different plastid functions in Plantago plastomes underwent positive selection, suggesting they might have contributed to enhancing species' adaptation during the evolutionary history of Plantago. While the most variable mutational hotspots in Plantago plastomes were not suitable for the development of species-specific molecular markers, species-specific polymorphisms could discriminate P. lanceolata from its closest relatives. Taken together, these results highlight the potential of plastome sequencing for the development of molecular markers to improve the identification of species with relevance in herbal products. [ABSTRACT FROM AUTHOR]

Genome skimming is a novel approach that enables obtaining large-scale genomic information based on high-copy DNA fractions from shallow whole-genome sequencing. The simplicity of this method, low analysis costs, and large amounts of generated data have made it widely used in plant research, including species identification, especially in the case of protected or endangered taxa. This task is particularly difficult in the case of closely related taxa. The Pinus mugo complex includes several dozen closely related taxa occurring in the most important mountain ranges in Europe. The taxonomic rank, origin, or distribution of many of these taxa have been debated for years. In this study, we used genome skimming and multilocus DNA barcoding approaches to obtain different sequence data sets and also to determine their genetic diversity and suitability for distinguishing closely related taxa in the Pinus mugo complex. We generated seven different data sets, which were then analyzed using three discrimination methods, i.e., tree based, distance based, and assembling species by automatic partitioning. Genetic diversity among populations and taxa was also investigated using haplotype network analysis and principal coordinate analysis. The proposed data set based on divergence hotspots is even twenty-times more variable than the other analyzed sets and improves the phylogenetic resolution of the Pinus mugo complex. In light of the obtained results, Pinus × rhaetica does not belong to the Pinus mugo complex and should not be identified with either Pinus uliginosa or Pinus rotundata. It seems to represent a fixed hybrid or introgressant between Pinus sylvestris and Pinus mugo. In turn, Pinus mugo and Pinus uncinata apparently played an important role in the origins of Pinus uliginosa and Pinus rotundata. [ABSTRACT FROM AUTHOR]

Simarouba, a neotropical genus in the family Simaroubaceae, currently lacks comprehensive genomic data in existing databases. This study aims to fill this gap by providing genomic resources for three Simarouba species, S. amara, S. versicolor, and S. glauca. It also aims to perform comparative molecular evolutionary analyses in relation to other species within the order Sapindales. The analysis of these three Simarouba species revealed the presence of the typical quadripartite structure expected in plastomes. However, some pseudogenization events were identified in the psbC, infA, rpl22, and ycf1 genes. In particular, the CDS of the psbC gene in S. amara was reduced from 1422 bp to 584 bp due to a premature stop codon. Nucleotide diversity data pointed to gene and intergenic regions as promising candidates for species and family discrimination within the group, specifically matK, ycf1, ndhF, rpl32, petA-psbJ, and trnS-trnG. Selection signal analyses showed strong evidence for positive selection on the rpl23 gene. Phylogenetic analyses indicated that S. versicolor and S. glauca have a closer phylogenetic relationship than S. amara. We provide chloroplast genomes of three Simaruba species and use them to elucidate plastome evolution, highlight the presence of pseudogenization, and identify potential DNA barcode regions. [ABSTRACT FROM AUTHOR]

Exploring the level of intraspecific diversity in taxa experienced radiation is helpful to understanding speciation and biodiversity assembly. Gentiana section Chondrophyllae sensu lato encompasses more than 180 species and occupies more a half of species in the genus. In this study, we collected samples across the range of three species (Gentiana aristata, G. crassuloides and G. haynaldii) in section Chondrophyllae s.l., and recovered the intra‐species variation by comparing with closely related taxon. Using 25 newly sequenced plastid genomes together with previously published data, we compared structural differences, quantified the variations in plastome size, and measured nucleotide diversity in various regions. Our results showed that the plastome size variation in the three Chondrophyllae species ranged from 285 to 628 bp, and the size variation in LSC, IR and SSC ranged from 236 to 898 bp, 52 to 393 bp and 135 to 356 bp, respectively. Nucleotide diversity of plastome or any of the four regions was much higher than the control species. The average nucleotide diversity in plastomes of the three species ranged from 0.0010 to 0.0023 in protein coding genes, and from 0.0023 to 0.0061 in intergenic regions. More repeat sequence variations were detected within the three Chondrophyllae species than the control species. Various plastid sequence matrixes resulted in different backbone topology in two target species, showed uncertainty in phylogenetic relationship based inference. In conclusion, our results recovered that species of G. section Chondrophyllae s.l. has high intraspecific plastome variation, and provided insights into the radiation in this speciose lineage. [ABSTRACT FROM AUTHOR]

Vanda R.Br. is an epiphytic orchid genus with significant horticultural and ornamental value. Previous molecular studies expanded Vanda including some members from five other genera. However, the interspecific relationships of this recently radiated genus have remained unclear based on several DNA markers until now. In this study, the complete plastome has been used to infer the phylogenetic relationships of Vanda s.l. The five newly obtained plastomes ranged from 146,340 bp to 149,273 bp in length, with a GC content ranging from 36.5% to 36.7%. The five plastomes contained 74 protein-coding genes (CDSs), 38 tRNAs, and 8 rRNAs, and their ndh genes underwent loss or pseudogenization. Comparative plastome analyses of 13 Vanda species revealed high conservation in terms of genome size, structure, and gene order, except for a large inversion from trnGGCC to ycf3 in V. coerulea. Moreover, six CDSs and five non-CDSs were selected as candidate DNA barcodes. Our phylogenetic analyses demonstrated that Vanda s.l. is a monophyletic group with high supporting values based on five different datasets (complete plastome with one IR, 68 CDSs, LSC, five hypervariable non-CDSs, and six hypervariable CDSs), while the phylogenetic relationships among species were fully resolved based on the complete plastome with one IR dataset. Our results confirmed that the complete plastome has a great power in resolving the phylogenetic relationships of recently radiated lineages. [ABSTRACT FROM AUTHOR]

Rorippa palustris Besser 1821, a species of Brassicaceae, is widely distributed around the world and used for both food and traditional Chinese medicinal purposes. Despite the plant's significance, its genetic diversity must be better understood. In this study, we have successfully assembled and characterized a complete plastome of R. palustris, marking a significant advancement toward comprehending its genetic composition. The plastome is 154,674 bp long and harbors 128 genes, including 83 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Our phylogenomic analysis indicated that R. palustris is closely related to R. curvipes. These findings are crucial for conserving and utilizing this important plant species. They also highlight the potential for future research into the evolution and preservation of R. palustris, which could be advantageous in pharmaceutical applications. [ABSTRACT FROM AUTHOR]

Dryas octopetala L. var. asiatica (Nakai) Nakai 1918 is a dwarf shrub that mainly grow in alpine and arctic zones of the Northern Hemisphere, representing an endemic variety in Asia. In the present study, the complete chloroplast (cp) genome of D. octopetala var. asiatica was first characterized and used for its phylogenetic analysis. The cp genome span 158,271 bp with an overall GC content of 36.5%. A total of 129 genes were identified, including 84 protein-coding genes (PCGs), 37 tRNA genes, and 8 rRNA genes. In addition, repetitive sequences and microsatellites were detected within this species. Phylogenetic analysis involving 39 cp genomes from Rosaceae family indicated that D. octopetala var. asiatica was sister to the clade of Amygdaloideae. This study contributes fundamental insights into the cp genome of Dryas octopetala var. asiatica, which will have expanded its use in photosynthesis and evolutionary study. [ABSTRACT FROM AUTHOR]

Red raspberries, Rubus idaeus L. 1753 are famous fruits which possess high value bioactive compounds. In this study, we report the complete chloroplast genome of R. idaeus, it displayed a typical quadripartite structure with 155687 bp in length. The genome encodes 127 genes including 79 protein coding genes, 8 rRNA genes and 40 tRNA genes, the overall GC content is 37.2%. Phylogenetic analysis revealed a close relationship between R. idaeus and R. sachalinensis in Section Malaehobatus. [ABSTRACT FROM AUTHOR]

Rorippa palustris Besser 1821, a species of Brassicaceae, is widely distributed around the world and used for both food and traditional Chinese medicinal purposes. Despite the plant’s significance, its genetic diversity must be better understood. In this study, we have successfully assembled and characterized a complete plastome of R. palustris, marking a significant advancement toward comprehending its genetic composition. The plastome is 154,674 bp long and harbors 128 genes, including 83 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Our phylogenomic analysis indicated that R. palustris is closely related to R. curvipes. These findings are crucial for conserving and utilizing this important plant species. They also highlight the potential for future research into the evolution and preservation of R. palustris, which could be advantageous in pharmaceutical applications.

Abstract Simarouba, a neotropical genus in the family Simaroubaceae, currently lacks comprehensive genomic data in existing databases. This study aims to fill this gap by providing genomic resources for three Simarouba species, S. amara, S. versicolor, and S. glauca. It also aims to perform comparative molecular evolutionary analyses in relation to other species within the order Sapindales. The analysis of these three Simarouba species revealed the presence of the typical quadripartite structure expected in plastomes. However, some pseudogenization events were identified in the psbC, infA, rpl22, and ycf1 genes. In particular, the CDS of the psbC gene in S. amara was reduced from 1422 bp to 584 bp due to a premature stop codon. Nucleotide diversity data pointed to gene and intergenic regions as promising candidates for species and family discrimination within the group, specifically matK, ycf1, ndhF, rpl32, petA-psbJ, and trnS-trnG. Selection signal analyses showed strong evidence for positive selection on the rpl23 gene. Phylogenetic analyses indicated that S. versicolor and S. glauca have a closer phylogenetic relationship than S. amara. We provide chloroplast genomes of three Simaruba species and use them to elucidate plastome evolution, highlight the presence of pseudogenization, and identify potential DNA barcode regions.

Dryas octopetala L. var. asiatica (Nakai) Nakai 1918 is a dwarf shrub that mainly grow in alpine and arctic zones of the Northern Hemisphere, representing an endemic variety in Asia. In the present study, the complete chloroplast (cp) genome of D. octopetala var. asiatica was first characterized and used for its phylogenetic analysis. The cp genome span 158,271 bp with an overall GC content of 36.5%. A total of 129 genes were identified, including 84 protein-coding genes (PCGs), 37 tRNA genes, and 8 rRNA genes. In addition, repetitive sequences and microsatellites were detected within this species. Phylogenetic analysis involving 39 cp genomes from Rosaceae family indicated that D. octopetala var. asiatica was sister to the clade of Amygdaloideae. This study contributes fundamental insights into the cp genome of Dryas octopetala var. asiatica, which will have expanded its use in photosynthesis and evolutionary study.

Red raspberries, Rubus idaeus L. 1753 are famous fruits which possess high value bioactive compounds. In this study, we report the complete chloroplast genome of R. idaeus, it displayed a typical quadripartite structure with 155687 bp in length. The genome encodes 127 genes including 79 protein coding genes, 8 rRNA genes and 40 tRNA genes, the overall GC content is 37.2%. Phylogenetic analysis revealed a close relationship between R. idaeus and R. sachalinensis in Section Malaehobatus.

Dracocephalum is a large genus comprises approximately 80 species of perennial herbs, mainly distributed in high elevation regions of temperate and Central Asia, with about half native to China. Within the genus, D. argunense and D. integrifolium are important herbs with great medicinal value. We sequenced plastomes of these two species for the first time. These plastomes showed a typical quadripartite structure and the length varied from 149,978 bp (D. integrifolium) to 150,802 bp (D. argunense). Plastomes of D. argunense and D. integrifolium included 127 and 133 genes, respectively. Phylogenetic analyses supported the monophyly of the redefined Dracocephalum and systematic relationships within the sampled species were well resolved. Our study added new genetic information about D. argunense and D. integrifolium and has great potential for further diversity studies, phylogenetic studies, and understanding of evolutionary history in Dracocephalum.

Paris xuefengshanensis, a new species collected from Hunan, China, is described and illustrated here based on phylogenetic and morphological evidence. Morphologically, it resembles P. thibetica and P. qiliangiana but can be distinguished by the shape of the leaf and sepal, the type of placenta and fruit. The phylogenetic analysis of the chloroplast genome revealed that P. xuefengshanensis does not belong to any section of the latest infrageneric taxonomy system, but form a well-supported independent monophyletic clade. Combined with morphology, we speculate that its distinctive phylogenetic position is related to the type of placenta (the transitional type between the parietal placenta and axile placenta). [ABSTRACT FROM AUTHOR]

Narcissus pseudonarcissus L. is one of the most iconic plants of the European flora. It is a species of great horticultural interest, but also an endangered and protected plant in the wild as a consequence of loss of natural habitats. Complete plastid genome was assembled from next-generation sequencing data obtaining a circular genome of 160,008 bp long assembly. It comprises a pair of inverted repeat regions, a large single-copy region (108,400 bp), and a small single-copy region (16,434 bp). It encodes 131 genes, including 87 protein coding genes, 37 tRNA genes and seven rRNA genes. Phylogeny showed the strict relationship between N. pseudonarcissus and Narcissus poeticus L. The complete plastome will provide a useful genetic resource for future conservation programmes, phylogenetic studies and horticultural applications.

The Ophioglossaceae family, one of the oldest orders of extant ferns, exhibits diverse morphological and chromosomal characteristics. This study presents the first complete plastome sequence of thermal adder’s-tongue fern (Ophioglossum thermale), a species renowned for its antioxidant properties in traditional Chinese medicine. Our analyses revealed 27 simple sequence repeats (SSRs) in the plastome, with variations in SSR frequencies compared to related genera. Our phylogenetic analyses placed O. thermale within the Ophioglossum s.s. clade, supporting previous studies and suggesting polyphyly within the genus Ophioglossum based on the sensu PPG I system. The enlarged noncoding regions in fern organelles (ENRFOs) resulting from foreign DNA insertions in O. thermale were identified in the ycf2-trnH and trnT-trnfM regions, similar to other Ophioglossum species. ENRFOs were found at the LSC and SSC, but not in IRs in Ophioglossaceae. Consequently, foreign DNA insertions and lineage-specific SSRs shed light on plastome evolution in the Ophioglossaceae family.

To elucidate the genetic information and evolutionary relationships of Swertia, we initiated the sequencing of the complete chloroplast genome of Swertia davidii Franch. 1888, complemented by comparative analyses with closely related species. The chloroplast genome of S. davidii was 153,516 bp in length and exhibited a typical quadripartite structure. It contained two regions with Inverted Repeat lengths of 25,767 bp, located between one Large Single-Copy region (83,617 bp) and one Short Single-Copy region (18,365 bp). The chloroplast genome of S. davidii encoded 132 genes, including 87 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The overall GC content was 38.15%. Maximum likelihood phylogenetic analysis of Swertia based on 26 available plastomes showed a close relationship between S. davidii and S. kouitchensi. This study will contribute to the genetic preservation of the species and the phylogenetic study of Swertia.

Polyspora axillaris (Roxb. ex Ker Gawl.) Sweet 1825, is a shrub or tree that is about 9 meters tall in the Theaceae family, mainly distributed in China and Vietnam, and it is widely used as a green tree species in many regions owing to its rapid growth and good adaptability. It is rich in various beneficial extracts for humans, but there are limited studies on it. In this study, we sequenced and annotated the complete plastome of P. axillaris. The chloroplast genome length of P. axillaris is 156,770 bp, with a total of 132 genes, including 37 tRNA genes, 8 rRNA genes and 87 protein-coding genes. The complete chloroplast genome of P. axillaris contains two Inverted Repeats (IRs) of 26,077 bp, a Large Single-Copy (LSC) region of 86,286 bp and a Small Single-Copy (SSC) region of 18,330 bp. The overall G/C content in the chloroplast is 37.3%. Phylogenetic inference shows that P. axillaris formed a sister relationship with P. hainanensis, along with 10 Theaceae species. The research result of P. axillaris will contribute to the genetic preservation of the species and the phylogenetic study of Polyspora.

Amaranthus roxburghianus H.W. Kung 1935, belonging to the Amaranthaceae family, is recognized for its significant medicinal properties. However, molecular research on this species has been limited. This study represents the inaugural documentation of the sequencing and assembly of the complete plastome of A. roxburghianus. The genome spans a total length of 149,969 base pairs (bp), exhibiting a conventional quadripartite structure. This structure comprises a large single-copy (LSC) region of 83,917 bp, a small single-copy (SSC) region of 18,124 bp, and two inverted repeat (IR) regions, each extending to 23,964 bp. In its entirety, the A. roxburghianus plastome encompasses 128 genes, of which 107 are unique, encompassing 77 individual protein-coding genes, 26 unique tRNA genes, and four unique rRNA genes. Phylogenetic analysis has shown a close resemblance between A. roxburghianus and A. polygonoides, both part of the subgenus Albersia. Although the genus Amaranthus is roughly divided into three subgenera, additional plastid genomic data are required for a more accurate assignment of A. albus and A. blitoides. The sequencing of this plastome is a significant step forward, likely to expedite the development of molecular markers and significantly contribute to genetic assays involving this distinctive species.

Abstract Background Heliotropiaceae is a family of the order Boraginales and has over 450 species. The members of the family Heliotropiaceae have been widely reported to be used in traditional medicine Over time, the classification of Heliotropiaceae has remained uncertain and has moved from family to subfamily, or conversely. Results In the present study, we sequenced, analyzed, and compared the complete plastomes of Euploca strigosa, Heliotropium arbainense, and Heliotropium longiflorum with the genomes of related taxa. The lengths of the plastomes of E. strigosa, H. arbainense, and H. longiflorum were 155,174 bp, 154,709 bp, and 154,496 bp, respectively. Each plastome consisted of 114 genes: 80 protein-coding genes, 4 ribosomal RNA genes, and 30 transfer RNA genes. The long repeats analysis indicated that reverse, palindromic, complement and forward repeats were all found in the three plastomes. The simple repeats analysis showed that the plastomes of E. strigosa, H. arbainense, and H. longiflorum contained 158, 165, and 151 microsatellites, respectively. The phylogenetic analysis confirmed two major clades in the Boraginales: clade I comprised Boraginaceae, while clade II included Heliotropiaceae, Ehretiaceae, Lennoaceae, and Cordiaceae. Inside the family Heliotropiaceae, E. strigosa is nested within the Heliotropium genus. Conclusions This study expands our knowledge of the evolutionary relationships within Heliotropiaceae and offers useful genetic resources.

Syzygium buxifolium. Hook. Et Arn.1833 is a member of the Myrtaceae family. This species is used in traditional Chinese medicines. It possesses numerous synonyms, reflecting the ambiguity in its taxonomy. The chloroplast genome has been widely used for species identification and phylogenetic analysis. Regrettably, there is a lack of information regarding the chloroplast genome of S. buxifolium. Here, we intend to obtain the chloroplast genome of S. buxifolium to resolve its classification problems. In particular, we utilized Illumina sequencing technology to sequence, GetOrganelle to assemble, and CPGAVAS2 to characterize the chloroplast genome of S. buxifolium. The chloroplast genome of S. buxifolium had a length of 158,581 bp and consisted of 111 unique genes, comprising 78 protein-coding genes, 29 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. In addition, we identified 86 Simple Sequence Repeats, 345 tandem repetitive sequences, and 34 dispersed repetitive sequences using modules implemented in CPGAVAS2. Lastly, we carried out phylogenetic analysis using Phylosuite. The results indicated a close relationship between S. buxifolium and S. grijsii. This study offers novel genetic data for the molecular identification and subsequent phylogenetic analysis of the Syzygium genus.

Abstract Background Caryodaphnopsis, a group of tropical trees (ca. 20 spp.) in the family Lauraceae, has an amphi-Pacific disjunct distribution: ten species are distributed in Southeast Asia, while eight species are restricted to tropical rainforests in South America. Previously, phylogenetic analyses using two nuclear markers resolved the relationships among the five species from Latin America. However, the phylogenetic relationships between the species in Asia remain poorly known. Results Here, we first determined the complete mitochondrial genome (mitogenome), plastome, and the nuclear ribosomal cistron (nrDNA) sequences of C. henryi with lengths of 1,168,029 bp, 154,938 bp, and 6495 bp, respectively. We found 2233 repeats and 368 potential SSRs in the mitogenome of C. henryi and 50 homologous DNA fragments between its mitogenome and plastome. Gene synteny analysis revealed a mass of rearrangements in the mitogenomes of Magnolia biondii, Hernandia nymphaeifolia, and C. henryi and only six conserved clustered genes among them. In order to reconstruct relationships for the ten Caryodaphnopsis species in Asia, we created three datasets: one for the mitogenome (coding genes and ten intergenic regions), another for the plastome (whole genome), and the other for the nuclear ribosomal cistron. All of the 22 Caryodaphnopsis individuals were divided into four, five, and six different clades in the phylogenies based on mitogenome, plastome, and nrDNA datasets, respectively. Conclusions The study showed phylogenetic conflicts within and between nuclear and organellar genome data of Caryodaphnopsis species. The sympatric Caryodaphnopsis species in Hekou and Malipo SW China may be related to the incomplete lineage sorting, chloroplast capture, and/or hybridization, which mixed the species as a complex in their evolutionary history.

Abstract In this study, the complete plastome sequence of Nigella sativa (black seed), was analyzed for the first time. The plastome spans approximately 154,120 bp, comprising four sections: the Large Single-Copy (LSC) (85,538 bp), the Small Single-Copy (SSC) (17,984 bp), and two Inverted Repeat (IR) regions (25,299 bp). A comparative study of N. sativa’s plastome with ten other species from various genera in the Ranunculaceae family reveals substantial structural variations. The contraction of the inverted repeat region in N. sativa influences the boundaries of single-copy regions, resulting in a shorter plastome size than other species. When comparing the plastome of N. sativa with those of its related species, significant divergence is observed, particularly except for N. damascena. Among these, the plastome of A. glaucifolium displays the highest average pairwise sequence divergence (0.2851) with N. sativa, followed by A. raddeana (0.2290) and A. coerulea (0.1222). Furthermore, the study identified 12 distinct hotspot regions characterized by elevated Pi values (> 0.1). These regions include trnH-GUG-psbA, matK-trnQ-UUG, psbK-trnR-UCU, atpF-atpI, rpoB-psbD, ycf3-ndhJ, ndhC-cemA, petA-psaJ, trnN-GUU-ndhF, trnV-GAC-rps12, ycf2-trnI-CAU, and ndhA-ycf1. Approximately, 24 tandem and 48 palindromic and forward repeats were detected in N. sativa plastome. The analysis revealed 32 microsatellites with the majority being mononucleotide repeats. In the N. sativa plastome, phenylalanine had the highest number of codons (1982 codons), while alanine was the least common amino acid with 260 codons. A phylogenetic tree, constructed using protein-coding genes, revealed a distinct monophyletic clade comprising N. sativa and N. damascene, closely aligned with the Cimicifugeae tribe and exhibiting robust support. This plastome provides valuable genetic information for precise species identification, phylogenetic resolution, and evolutionary studies of N. sativa.

Introduction: The genus Acronema, belonging to Apiaceae, includes approximately 25 species distributed in the high-altitude Sino-Himalayan region from E Nepal to SW China. This genus is a taxonomically complex genus with often indistinct species boundaries and problematic generic delimitation with Sinocarum and other close genera, largely due to the varied morphological characteristics. Methods: To explore the phylogenetic relationships and clarify the limits of the genus Acronema and its related genera, we reconstructed a reliable phylogenetic framework with high support and resolution based on two molecular datasets (plastome data and ITS sequences) and performed morphological analyses. Results: Both phylogenetic analyses robustly supported that Acronema was a non-monophyletic group that fell into two clades: Acronema Clade and East-Asia Clade. We also newly sequenced and assembled sixteen Acronema complete plastomes and performed comprehensively comparative analyses for this genus. The comparative results showed that the plastome structure, gene number, GC content, codon bias patterns were high similarity, but varied in borders of SC/IR and we identified six different types of SC/IR border. The SC/IR boundaries of Acronema chienii were significantly different from the other Acronema members which was consistent with the type VI pattern in the genus Tongoloa. We also identified twelve potential DNA barcode regions (ccsA, matK, ndhF, ndhG, psaI, psbI, rpl32, rps15, ycf1, ycf3, psaI-ycf4 and psbM-trnD) for species identification in Acronema. The molecular evolution of Acronema was relatively conservative that only one gene (petG) was found to be under positive selection (ω = 1.02489). Discussion: The gene petG is one of the genes involved in the transmission of photosynthetic electron chains during photosynthesis, which plays a crucial role in the process of photosynthesis in plants. This is also a manifestation of the adaptive evolution of plants in high-altitude areas to the environment. In conclusion, our study provides novel insights into the plastome adaptive evolution, phylogeny, and taxonomy of genus Acronema. [ABSTRACT FROM AUTHOR]

The genus Amomum includes over 111 species, 6 of which are widely utilized as medicinal plants and have already undergone taxonomic revision. Due to their morphological similarities, the presence of counterfeit and substandard products remains a challenge. Accurate plant identification is, therefore, essential to address these issues. This study utilized 11 newly sequenced samples and extensive NCBI data to perform molecular identification of the six medicinal "Doukou" species. The plastomes of these species exhibited a typical quadripartite structure with a conserved gene content. However, independent variation shifts of the SC/IR boundaries existed between and within species. The comprehensive set of genetic sequences, including ITS, ITS1, ITS2, complete plastomes, matK, rbcL, psbA-trnH, and ycf1, showed varying discrimination of the six "Doukou" species based on both distance and phylogenetic tree methods. Among these, the ITS, ITS1, and complete plastome sequences demonstrated the highest identification success rate (3/6), followed by ycf1 (2/6), and then ITS2, matK, and psbA-trnH (1/6). In contrast, rbcL failed to identify any species. This research established a basis for a reliable molecular identification method for medicinal "Doukou" plants to protect wild plant resources, promote the sustainable use of medicinal plants, and restrict the exploitation of these resources. [ABSTRACT FROM AUTHOR]

The marine prasinophyte green algae Pycnococcus provasolii and Pseudoscourfieldia marina represent the only extant genera and known species of the Pycnococcaceae. However, their taxonomic status needs to be reassessed, owing to the very close relationship inferred from previous sequence comparisons of individual genes. Although Py. provasolii and Ps. marina are morphologically different, their plastid rbcL and nuclear small subunit rRNA genes were observed to be nearly or entirely identical in sequence, thus leading to the hypothesis that they represent distinct growth forms or alternate life‐cycle stages of the same organism. To evaluate this hypothesis, we used organelle genomes as molecular markers. The plastome and mitogenome of Ps. marina UIO 007 were sequenced and compared with those available for two isolates of Py. provasolii (CCMP 1203 and CCAP 190/2). The Ps. marina organelle genomes proved to be almost identical in size and had the same gene content and gene order as their Py. provasolii counterparts. Single nucleotide substitutions and insertions/deletions were localized using genome‐scale sequence alignments. Over 99.70% sequence identities were observed in all pairwise comparisons of plastomes and mitogenomes. Alignments of both organelle genomes revealed that Ps. marina UIO 007 is closer to Py. provasolii CCAP 190/2 than are the two Py. provasolii strains to one another. Therefore, our results are not consistent with the placement of Ps. marina and Py. provasolii strains into distinct genera. We propose a taxonomic revision of the Pycnococcaceae and the erection of a new class of Chlorophyta, the Pseudoscourfieldiophyceae. [ABSTRACT FROM AUTHOR]

Mazzaella, a genus with no genomic resources available, has extensive distribution in the cold waters of the Pacific, where they represent ecologically and economically important species. In this study, we aimed to sequence, assemble, and annotate the complete mitochondrial and chloroplast genomes from two Mazzaella spp. and characterize the intraspecific variation among them. We report for the first time seven whole organellar genomes (mitochondria: OR915856, OR947465, OR947466, OR947467, OR947468, OR947469, OR947470; chloroplast: OR881974, OR909680, OR909681, OR909682, OR909683, OR909684, OR909685) obtained through high‐throughput sequencing for six M. laminarioides sampled from three Chilean regions and one M. membranacea. Sequenced Mazzaella mitogenomes have identical gene number, gene order, and genome structure. The same results were observed for assembled plastomes. A total of 52 genes were identified in mitogenomes, and a total of 235 genes were identified in plastomes. Although the M. membranacea plastome included a full‐length pbsA gene, in all M. laminarioides samples, the pbsA gene was split in three open reading frames (ORFs). Within M. laminarioides, we observed important plastome lineage‐specific variations, such as the pseudogenization of the two hypothetical protein‐coding genes, ycf23 and ycf45. Nonsense mutations in the ycf23 and ycf45 genes were only detected in the northern lineage. These results are consistent with phylogenetic reconstructions and divergence time estimation using concatenated coding sequences that not only support the monophyly of M. laminarioides but also underscore that the three M. laminarioides lineages are in an advanced stage of divergence. These new results open the question of the existence of still undisclosed species in M. laminarioides. [ABSTRACT FROM AUTHOR]

Narcissus pseudonarcissus L. is one of the most iconic plants of the European flora. It is a species of great horticultural interest, but also an endangered and protected plant in the wild as a consequence of loss of natural habitats. Complete plastid genome was assembled from next-generation sequencing data obtaining a circular genome of 160,008 bp long assembly. It comprises a pair of inverted repeat regions, a large single-copy region (108,400 bp), and a small single-copy region (16,434 bp). It encodes 131 genes, including 87 protein coding genes, 37 tRNA genes and seven rRNA genes. Phylogeny showed the strict relationship between N. pseudonarcissus and Narcissus poeticus L. The complete plastome will provide a useful genetic resource for future conservation programmes, phylogenetic studies and horticultural applications. [ABSTRACT FROM AUTHOR]

To elucidate the genetic information and evolutionary relationships of Swertia, we initiated the sequencing of the complete chloroplast genome of Swertia davidii Franch. 1888, complemented by comparative analyses with closely related species. The chloroplast genome of S. davidii was 153,516 bp in length and exhibited a typical quadripartite structure. It contained two regions with Inverted Repeat lengths of 25,767 bp, located between one Large Single-Copy region (83,617 bp) and one Short Single-Copy region (18,365 bp). The chloroplast genome of S. davidii encoded 132 genes, including 87 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The overall GC content was 38.15%. Maximum likelihood phylogenetic analysis of Swertia based on 26 available plastomes showed a close relationship between S. davidii and S. kouitchensi. This study will contribute to the genetic preservation of the species and the phylogenetic study of Swertia. [ABSTRACT FROM AUTHOR]

The Ophioglossaceae family, one of the oldest orders of extant ferns, exhibits diverse morphological and chromosomal characteristics. This study presents the first complete plastome sequence of thermal adder's-tongue fern (Ophioglossum thermale), a species renowned for its antioxidant properties in traditional Chinese medicine. Our analyses revealed 27 simple sequence repeats (SSRs) in the plastome, with variations in SSR frequencies compared to related genera. Our phylogenetic analyses placed O. thermale within the Ophioglossum s.s. clade, supporting previous studies and suggesting polyphyly within the genus Ophioglossum based on the sensu PPG I system. The enlarged noncoding regions in fern organelles (ENRFOs) resulting from foreign DNA insertions in O. thermale were identified in the ycf2-trnH and trnT-trnfM regions, similar to other Ophioglossum species. ENRFOs were found at the LSC and SSC, but not in IRs in Ophioglossaceae. Consequently, foreign DNA insertions and lineage-specific SSRs shed light on plastome evolution in the Ophioglossaceae family. [ABSTRACT FROM AUTHOR]

Background: Heliotropiaceae is a family of the order Boraginales and has over 450 species. The members of the family Heliotropiaceae have been widely reported to be used in traditional medicine Over time, the classification of Heliotropiaceae has remained uncertain and has moved from family to subfamily, or conversely. Results: In the present study, we sequenced, analyzed, and compared the complete plastomes of Euploca strigosa, Heliotropium arbainense, and Heliotropium longiflorum with the genomes of related taxa. The lengths of the plastomes of E. strigosa, H. arbainense, and H. longiflorum were 155,174 bp, 154,709 bp, and 154,496 bp, respectively. Each plastome consisted of 114 genes: 80 protein-coding genes, 4 ribosomal RNA genes, and 30 transfer RNA genes. The long repeats analysis indicated that reverse, palindromic, complement and forward repeats were all found in the three plastomes. The simple repeats analysis showed that the plastomes of E. strigosa, H. arbainense, and H. longiflorum contained 158, 165, and 151 microsatellites, respectively. The phylogenetic analysis confirmed two major clades in the Boraginales: clade I comprised Boraginaceae, while clade II included Heliotropiaceae, Ehretiaceae, Lennoaceae, and Cordiaceae. Inside the family Heliotropiaceae, E. strigosa is nested within the Heliotropium genus. Conclusions: This study expands our knowledge of the evolutionary relationships within Heliotropiaceae and offers useful genetic resources. [ABSTRACT FROM AUTHOR]

The hemiparasitic tribe Cymbarieae (Orobanchaceae) plays a crucial role in elucidating the initial stage of the transition from autotrophism to heterotrophism. However, the complete chloroplast genome of the type genus Cymbaria has yet to be reported. In addition, the traditional Mongolian medicine Cymbaria daurica is frequently subjected to adulteration or substitution because of the minor morphological differences with Cymbaria mongolica. In this study, the complete chloroplast genomes of the two Cymbaria species were assembled and annotated, and those of other published 52 Orobanchaceae species were retrieved for comparative analyses. We found that the Cymbaria chloroplast genomes are characterized by pseudogenization or loss of stress‐relevant genes (ndh) and a unique rbcL–matK inversion. Unlike the high variability observed in holoparasites, Cymbaria and other hemiparasites exhibit high similarity to autotrophs in genome size, guanine–cytosine (GC) content, and intact genes. Notably, four pairs of specific DNA barcodes were developed and validated to distinguish the medicinal herb from its adulterants. Phylogenetic analyses revealed that the genus Cymbaria and the Schwalbea–Siphonostegia clade are grouped into the tribe Cymbarieae, which forms a sister clade to the remaining Orobanchaceae parasitic lineages. Moreover, the diversification of monophyletic Cymbaria occurred during the late Miocene (6.72 Mya) in the Mongol–Chinese steppe region. Our findings provide valuable genetic resources for studying the phylogeny of Orobanchaceae and plant parasitism, and genetic tools to validate the authenticity of the traditional Mongolian medicine "Xinba." [ABSTRACT FROM AUTHOR]

Reevesia is an eastern Asian-eastern North American disjunction genus in the family Malvaceae s.l. and comprises approximately 25 species. The relationships within the genus are not well understood. Here, 15 plastomes representing 12 Reevesia species were compared, with the aim of better understanding the species circumscription and phylogenetic relationships within the genus and among genera in the family Malvaceae s.l. The 11 newly sequenced plastomes range between 161,532 and 161, 945 bp in length. The genomes contain 114 unique genes, 18 of which are duplicated in the inverted repeats (IRs). Gene content of these plastomes is nearly identical. All the protein-coding genes are under purifying selection in the Reevesia plastomes compared. The top ten hypervariable regions, SSRs, and the long repeats identified are potential molecular markers for future population genetic and phylogenetic studies. Phylogenetic analysis based on the whole plastomes confirmed the monophyly of Reevesia and a close relationship with Durio (traditional Bombacaceae) in subfamily Helicteroideae, but not with the morphologically similar genera Pterospermum and Sterculia (both of traditional Sterculiaceae). Phylogenetic relationships within Reevesia suggested that two species, R. pubescens and R. thyrsoidea, as newly defined, are not monophyletic. Six taxa, R. membranacea, R. xuefengensis, R. botingensis, R. lofouensis, R. longipetiolata and R. pycnantha, are suggested to be recognized. [ABSTRACT FROM AUTHOR]

The species Peucedanum ledebourielloides , a medicinally important herb, has previously been placed in Peucedanum s.l. based on dorsally compressed mericarps with slightly prominent dorsal ribs and narrowly winged lateral ribs. However, this genus has now been re-delimited in a narrow sense, namely Peucedanum s.s. , further recognized by ternate leaves and glabrous plants, so that the taxonomic position of P. ledebourielloides is unknown. To investigate the taxonomic position of this species, we sequenced and assembled the complete plastomes for two samples of P. ledebourielloides. Phylogenetic analyses based on 79 protein-coding genes showed that the samples of P. ledebourielloides formed a separate clade and were distant from Peucedanum morisonii , a representative member of Peucedanum s.s. , implying that P. ledebourielloides cannot not be placed in Peucedanum s.s. Additionally, plastome comparisons and chromosome studies indicated the clear specificity of P. ledebourielloides. In particular, pinnate leaves and dorsally compressed mericarps densely covered with forked scabrous bristles, slightly prominent dorsal ribs, narrowly winged lateral ribs, and one vitta in each furrow and two vittae on the commissure clearly distinguished P. ledebourielloides from Peucedanum s.s. and other genera of Apiaceae. Hence, a new genus, Pseudopeucedanum gen. nov. was established to accommodate this species. Our results improve the taxonomy of the family Apiaceae and provide guidance for the taxonomic revision of other taxa that are difficult to place systematically. [ABSTRACT FROM AUTHOR]

Bryophytes, a monophyletic group comprising three major lineages, diversified soon after the terrestrialization of land plants. However, their internal phylogenetic relationships remain controversial. In this study, we reconstructed the ordinal and familial phylogeny of bryophytes using the largest plastid data set to date, including 549 taxa that represent almost all known orders and two‐thirds of families. The strongly supported phylogenetic inference enabled us to propose in mosses seven newly segregated families, that is, Baldwiniellaceae, Calyptrochaetaceae, Ctenidiaceae, Herpetineuraceae, Isodrepaniaceae, Pseudotaxiphyllaceae, and Rozeaceae, and one reduced family, that is, Climaciaceae. We also transferred the liverwort family Calyculariaceae from Fossombroniales to Pelliales. Recent advancements in molecular phylogeny have revolutionized bryophyte classification, tending to be more fragmental. Hence, we further propose a revised familial classification system for bryophytes that includes 45 orders and 142 families in mosses, 23 orders and 85 families in liverworts, and five orders and five families in hornworts. [ABSTRACT FROM AUTHOR]

Polyspora axillaris (Roxb. ex Ker Gawl.) Sweet 1825, is a shrub or tree that is about 9 meters tall in the Theaceae family, mainly distributed in China and Vietnam, and it is widely used as a green tree species in many regions owing to its rapid growth and good adaptability. It is rich in various beneficial extracts for humans, but there are limited studies on it. In this study, we sequenced and annotated the complete plastome of P. axillaris. The chloroplast genome length of P. axillaris is 156,770 bp, with a total of 132 genes, including 37 tRNA genes, 8 rRNA genes and 87 protein-coding genes. The complete chloroplast genome of P. axillaris contains two Inverted Repeats (IRs) of 26,077 bp, a Large Single-Copy (LSC) region of 86,286 bp and a Small Single-Copy (SSC) region of 18,330 bp. The overall G/C content in the chloroplast is 37.3%. Phylogenetic inference shows that P. axillaris formed a sister relationship with P. hainanensis, along with 10 Theaceae species. The research result of P. axillaris will contribute to the genetic preservation of the species and the phylogenetic study of Polyspora. [ABSTRACT FROM AUTHOR]

Amaranthus roxburghianus H.W. Kung 1935, belonging to the Amaranthaceae family, is recognized for its significant medicinal properties. However, molecular research on this species has been limited. This study represents the inaugural documentation of the sequencing and assembly of the complete plastome of A. roxburghianus. The genome spans a total length of 149,969 base pairs (bp), exhibiting a conventional quadripartite structure. This structure comprises a large single-copy (LSC) region of 83,917 bp, a small single-copy (SSC) region of 18,124 bp, and two inverted repeat (IR) regions, each extending to 23,964 bp. In its entirety, the A. roxburghianus plastome encompasses 128 genes, of which 107 are unique, encompassing 77 individual protein-coding genes, 26 unique tRNA genes, and four unique rRNA genes. Phylogenetic analysis has shown a close resemblance between A. roxburghianus and A. polygonoides, both part of the subgenus Albersia. Although the genus Amaranthus is roughly divided into three subgenera, additional plastid genomic data are required for a more accurate assignment of A. albus and A. blitoides. The sequencing of this plastome is a significant step forward, likely to expedite the development of molecular markers and significantly contribute to genetic assays involving this distinctive species. [ABSTRACT FROM AUTHOR]

Syzygium buxifolium. Hook. Et Arn.1833 is a member of the Myrtaceae family. This species is used in traditional Chinese medicines. It possesses numerous synonyms, reflecting the ambiguity in its taxonomy. The chloroplast genome has been widely used for species identification and phylogenetic analysis. Regrettably, there is a lack of information regarding the chloroplast genome of S. buxifolium. Here, we intend to obtain the chloroplast genome of S. buxifolium to resolve its classification problems. In particular, we utilized Illumina sequencing technology to sequence, GetOrganelle to assemble, and CPGAVAS2 to characterize the chloroplast genome of S. buxifolium. The chloroplast genome of S. buxifolium had a length of 158,581 bp and consisted of 111 unique genes, comprising 78 protein-coding genes, 29 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes. In addition, we identified 86 Simple Sequence Repeats, 345 tandem repetitive sequences, and 34 dispersed repetitive sequences using modules implemented in CPGAVAS2. Lastly, we carried out phylogenetic analysis using Phylosuite. The results indicated a close relationship between S. buxifolium and S. grijsii. This study offers novel genetic data for the molecular identification and subsequent phylogenetic analysis of the Syzygium genus. [ABSTRACT FROM AUTHOR]

Background: Caryodaphnopsis, a group of tropical trees (ca. 20 spp.) in the family Lauraceae, has an amphi-Pacific disjunct distribution: ten species are distributed in Southeast Asia, while eight species are restricted to tropical rainforests in South America. Previously, phylogenetic analyses using two nuclear markers resolved the relationships among the five species from Latin America. However, the phylogenetic relationships between the species in Asia remain poorly known. Results: Here, we first determined the complete mitochondrial genome (mitogenome), plastome, and the nuclear ribosomal cistron (nrDNA) sequences of C. henryi with lengths of 1,168,029 bp, 154,938 bp, and 6495 bp, respectively. We found 2233 repeats and 368 potential SSRs in the mitogenome of C. henryi and 50 homologous DNA fragments between its mitogenome and plastome. Gene synteny analysis revealed a mass of rearrangements in the mitogenomes of Magnolia biondii, Hernandia nymphaeifolia, and C. henryi and only six conserved clustered genes among them. In order to reconstruct relationships for the ten Caryodaphnopsis species in Asia, we created three datasets: one for the mitogenome (coding genes and ten intergenic regions), another for the plastome (whole genome), and the other for the nuclear ribosomal cistron. All of the 22 Caryodaphnopsis individuals were divided into four, five, and six different clades in the phylogenies based on mitogenome, plastome, and nrDNA datasets, respectively. Conclusions: The study showed phylogenetic conflicts within and between nuclear and organellar genome data of Caryodaphnopsis species. The sympatric Caryodaphnopsis species in Hekou and Malipo SW China may be related to the incomplete lineage sorting, chloroplast capture, and/or hybridization, which mixed the species as a complex in their evolutionary history. [ABSTRACT FROM AUTHOR]

The orchid genus Dipodium R.Br. (Epidendroideae) comprises leafy autotrophic and leafless mycoheterotrophic species, with the latter confined to sect. Dipodium. This study examined plastome degeneration in Dipodium in a phylogenomic and temporal context. Whole plastomes were reconstructed and annotated for 24 Dipodium samples representing 14 species and two putatively new species, encompassing over 80% of species diversity in sect. Dipodium. Phylogenomic analysis based on 68 plastid loci including a broad outgroup sampling across Orchidaceae found that sect. Leopardanthus is the sister lineage to sect. Dipodium. Dipodium ensifolium, the only leafy autotrophic species in sect. Dipodium, was found to be a sister to all leafless, mycoheterotrophic species, supporting a single evolutionary origin of mycoheterotrophy in the genus. Divergence-time estimations found that Dipodium arose ca. 33.3 Ma near the lower boundary of the Oligocene and that crown diversification commenced in the late Miocene, ca. 11.3 Ma. Mycoheterotrophy in the genus was estimated to have evolved in the late Miocene, ca. 7.3 Ma, in sect. Dipodium. The comparative assessment of plastome structure and gene degradation in Dipodium revealed that plastid ndh genes were pseudogenised or physically lost in all Dipodium species, including in leafy autotrophic species of both Dipodium sections. Levels of plastid ndh gene degradation were found to vary among species as well as within species, providing evidence of relaxed selection for retention of the NADH dehydrogenase complex within the genus. Dipodium exhibits an early stage of plastid genome degradation, as all species were found to have retained a full set of functional photosynthesis-related genes and housekeeping genes. This study provides important insights into plastid genome degradation along the transition from autotrophy to mycoheterotrophy in a phylogenomic and temporal context. [ABSTRACT FROM AUTHOR]

Introduction: The genus Sanicula L. is a taxonomically complicated taxa within Apiaceae, as its high variability in morphology. Although taxonomists have performed several taxonomic revisions for this genus, the interspecific relationships and species boundaries have not been satisfactorily resolved, especially for those endemic to China. This study mainly focused on S. giraldii var. ovicalycina, S. tienmuensis var. pauciflora, and S. orthacantha var. stolonifera and also described two new members of the genus. Methods: We newly sequenced sixteen plastomes from nine Sanicula species. Combined with eleven plastomes previously reported by us and one plastome downloaded, we performed a comprehensively plastid phylogenomics analysis of 21 Sanicula taxa. Results and Discussion: The comparative results showed that 21 Sanicula plastomes in their structure and features were highly conserved and further justified that two new species were indeed members of Sanicula. Nevertheless, eleven mutation hotspot regions were still identified. Phylogenetic analyses based on plastome data and the ITS sequences strongly supported that these three varieties were clearly distant from three type varieties. The results implied that these three varieties should be considered as three independent species, which were further justified by their multiple morphological characters. Therefore, revising these three varieties into three independent species was reasonable and convincing. Moreover, we also identified and described two new Sanicula species (S. hanyuanensis and S. langaoensis) from Sichuan and Shanxi, China, respectively. Based on their distinct morphological characteristics and molecular phylogenetic analysis, two new species were included in Sanicula. In summary, our study impelled the revisions of Sanicula members and improved the taxonomic system of the genus. [ABSTRACT FROM AUTHOR]

Despite extensive research into the phylogenetic relationships of the genus Magnolia, Neotropical taxa have been neglected. This is partly because their numbers have recently doubled and now account for almost half of the global richness. Therefore, by sampling one-third of all Neotropical taxa their relationships were studied using morphological, nuclear, and plastome data. Two major clades were identified: Clade I, comprising Magnolia sect. Talauma, Magnolia sect. Splendentes from the Neotropics, and the Asian Magnolia sect. Gwillimia; while Clade II included the Neotropical clades Magnolia sect. Macrophylla and Magnolia sect. Magnolia, along with the remaining non-Neotropical sections. Within Clade I, Magnolia sect. Talauma was geographically divided into a northern subclade grouping Mexican and Central American taxa, and a southern subclade comprising South American and Caribbean taxa. Magnolia sect. Splendentes was also dichotomously divided, corresponding to the former Magnolia sect. Talauma subsect. Cubenses and Magnolia sect. Talauma subsect. Dugandiodendron. In Clade II, the relationships within Magnolia sect. Macrophylla and Magnolia sect. Magnolia were unclear, suggesting a species complex in all Magnolia sect. Macrophylla taxa. In total, 25 morphological traits were assessed, and ancestral state reconstructions were carried out. Only the joined clustering of mature follicles was a synapomorphy for the southern subclade of Magnolia sect. Talauma. In conclusion, this highlights the need to re-assess the taxonomic delimitation of certain groups, to update the infrageneric classification of Neotropical clades and to explore morphological traits to support them.

Abstract Exploring the level of intraspecific diversity in taxa experienced radiation is helpful to understanding speciation and biodiversity assembly. Gentiana section Chondrophyllae sensu lato encompasses more than 180 species and occupies more a half of species in the genus. In this study, we collected samples across the range of three species (Gentiana aristata, G. crassuloides and G. haynaldii) in section Chondrophyllae s.l., and recovered the intra‐species variation by comparing with closely related taxon. Using 25 newly sequenced plastid genomes together with previously published data, we compared structural differences, quantified the variations in plastome size, and measured nucleotide diversity in various regions. Our results showed that the plastome size variation in the three Chondrophyllae species ranged from 285 to 628 bp, and the size variation in LSC, IR and SSC ranged from 236 to 898 bp, 52 to 393 bp and 135 to 356 bp, respectively. Nucleotide diversity of plastome or any of the four regions was much higher than the control species. The average nucleotide diversity in plastomes of the three species ranged from 0.0010 to 0.0023 in protein coding genes, and from 0.0023 to 0.0061 in intergenic regions. More repeat sequence variations were detected within the three Chondrophyllae species than the control species. Various plastid sequence matrixes resulted in different backbone topology in two target species, showed uncertainty in phylogenetic relationship based inference. In conclusion, our results recovered that species of G. section Chondrophyllae s.l. has high intraspecific plastome variation, and provided insights into the radiation in this speciose lineage.

IntroductionThis study presents the first complete plastome (cpDNA) sequence of Psydrax latifolia, a member of the Rubiaceae family, which includes small trees, smooth shrubs, and occasionally lianas. This specimen was collected near the Red Sea coast in Jazan province, Saudi Arabia, specifically in the paleotropical Fifa Mountains. The research aimed to characterize and compare the plastome of Psydrax latifolia with other species in the Rubiaceae family to enhance our understanding of its evolutionary dynamics and phylogenetic relationships.MethodsThe plastome of P. latifolia was sequenced and reconstructed using whole-genome next-generation sequencing (NGS) techniques. Comparative analyses were performed between the plastome of P. latifolia and 16 other species within the Rubiaceae family to identify genomic features and evolutionary patterns. The plastome structure, gene content, and codon usage were analyzed, with a focus on the Relative Synonymous Codon Usage (RSCU) in different regions of the plastome.ResultsThe plastome of P. latifolia was found to be 153,242 base pairs (bp) in length, including a large single copy (LSC) region of 83,603 bp, a small single copy (SSC) region of 18,115 bp, and a pair of inverted repeats (IRs) of 25,762 bp each. It contained 87 protein-coding genes, 8 rRNA genes, and 33 tRNA genes, with an overall GC content of 37.30%. The RSCU analysis revealed regional variation, with the protein-coding region being more conserved than the intergenic spacer.DiscussionThis study provides the first complete plastome sequence of Psydrax latifolia, offering insights into its genomic structure and phylogenetic position within the Rubiaceae family. Comparative analyses with 16 Rubiaceae species highlighted distinct genomic features and evolutionary patterns. These findings contribute to the understanding of plastome evolution in the Rubiaceae family and provide a valuable resource for future phylogenetic and evolutionary studies.