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The genus Argentina Hill belongs to the tribe Potentilleae Sweet and contains approximately 75 species predominantly distributed in the Sino-Himalayan region and the Malesian archipelago. So far we have less knowledge on the phylogenetic relationships within Argentina owing to limited sampling of Argentina taxa or gene fragments in previous studies. Moreover, to date there is no phylogenetic study on Argentina from the perspective of comparative chloroplast (cp) genomics. Here we performed comparative genomic analyses on the cp genomes of 39 accessions representing 18 taxa of Argentina. The Argentina cp genomes presented the typical quadripartite structure, with the sizes ranging from 155 096 bp to 157 166 bp. The 39 Argentina cp genomes contained a set of 112 unique genes, comprising four ribosomal RNA (rRNA) genes, 30 transfer RNA (tRNA) genes, as well as 78 protein-coding genes (PCGs). The cp genome organization, gene content and order in Argentina were highly conserved, but some visible divergences were present in IR/SC boundary regions. Ten regions (trnH-GUG-psbA, trnG-GCC-trnfM-CAU, trnD-GUC-trnY-GUA, rpl32-trnL-UAG, atpH-atpI, rps16-trnQ-UUG, trnS-GCU-trnG-UCC, ndhF-rpl32, trnR-UCU-atpA, and accD-psaI) were identified as excellent candidate DNA markers for future studies on species identification, population genetics and phylogeny of Argentina. Our results indicated that Argentina is monophyletic. In the current sampling, the A. smithiana - A. anserina clade was sister to the remainder of Argentina. Our results corroborated the previous taxonomic treatments to transfer A. phanerophlebia and A. micropetala from the genus Sibbaldia L. to Argentina. Our results showed close relationships among A. stenophylla, A. microphylla, A. taliensis, and A. tatsienluensis, congruent with previous studies based on the morphology of these species. Twenty-six genes (rps3, rps15, rps16, rps19, rpl16, rpl20, rpl22, rpoA, rpoB, rpoC1, rpoC2, atpA, atpF, psbB, psbF, ndhA, ndhB, ndhC, ndhD, ndhF, rbcL, accD, ccsA, matK, ycf1, ycf2) were with sites under positive selection, and adaptive evolution of these genes might have played crucial roles in Argentina species adaptation to the harsh mountain environment. This study will facilitate future work on taxonomy, phylogenetics, and adaptive evolution of Argentina.
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Agave durangensis commonly known as agave cenizo, is an endemic Agave species in Mexico used for mescal production, yet its taxonomic delimitation is still controversial. This study aimed to enhance taxonomic clarity by characterizing its chloroplast genome. Chloroplast DNA was isolated from 2-year-old A. durangensis leaves. The complete chloroplast genome size was 156,441 bp, comprising a large single-copy region (LSC), a pair of inverted repeat regions (IR), and a small single-copy region (SSC). Annotation revealed 87 protein-coding genes, 38 tRNAs, and 8 rRNAs, with notable gene inversions. Phylogenetic analysis suggests, A. durangensis forms a separate lineage within the Agave genus.
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OBJECTIVES: The Peruvian Andean region is an important center for plant domestication. However, to date, there have been few genetic studies on native grain, which limits our understanding of their genetic diversity and the development of new genetic studies for their breeding. Herein, we revealed the plastid genome of Chenopodium petiolare to expand our knowledge of its molecular markers, evolutionary studies, and conservation genetics. DATA DESCRIPTION: Total genomic DNA was extracted from fresh leaves (voucher: USM < PER > :MHN333570). The DNA was sequenced using Illumina Novaseq 6000 (Macrogen Inc., Seoul, Republic of Korea) and reads 152,064 bp in length, with a large single-copy region of 83,520 bp and small single-copy region of 18,108 bp were obtained. These reads were separated by a pair of inverted repeat regions (IR) of 25,218 bp, and the overall guanine and cytosine (GC) was 37.24%. The plastid genome contains 130 genes (111 genes were unique and 19 genes were found duplicated in each IR region), including 86 protein-coding genes, 36 transfer RNA-coding genes, eight ribosomal RNA-coding genes, and 25 genes with introns (21 genes with one intron and four genes with two introns). The phylogenetic tree reconstructed based on single-copy orthologous genes and maximum likelihood analysis indicated that Chenopodium petiolare is most closely related to Chenopodium quinoa.
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Chenopodium , Genoma del Cloroplasto , Genoma de Plastidios , Perú , Filogenia , Chenopodium/genética , Fitomejoramiento , ADNRESUMEN
Psittacanthus schiedeanus (Cham. & Schltdl.) G.Don., 1834, is a mistletoe species in the Loranthaceae, characteristic of the canopy in cloud forest edges and widely distributed in northern Mesoamerica. Here, we report the complete chloroplast genome sequence of P. schiedeanus, the first for a species in the Psittacantheae tribe. The circularized quadripartite structure of the P. schiedeanus chloroplast genome was 122,586 bp in length and included a large single-copy region of 72,507 bp and two inverted repeats of 21,283 bp separated by a small single-copy region of 7,513 bp. The genome contained 112 genes, of which 96 are unique, including 65 protein-coding genes, 27 transfer RNA, and four ribosomal RNA. The overall GC content in the plastome of P. schiedeanus is 36.9%. Based on 43 published complete chloroplast genome sequences for species in the families Loranthaceae and Santalaceae (Santalales), the maximum-likelihood phylogenetic tree with high-support bootstrap values indicated that P. schiedeanus in the Psittacantheae tribe is sister to the tribe Lorantheae. The chloroplast genome provided in this study represents a valuable resource for genetic, phylogenetic and conservation studies of Psittacanthus species, and an important advance for unraveling the evolutionary history of these hemiparasitic plants.
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BACKGROUND: Neltuma pallida is a tree that grows in arid soils in northwestern Peru. As a predominant species of the Equatorial Dry Forest ecoregion, it holds significant economic and ecological value for both people and environment. Despite this, the species is severely threatened and there is a lack of genetic and genomic research, hindering the proposal of evidence-based conservation strategies. RESULTS: In this work, we conducted the assembly, annotation, analysis and comparison of the chloroplast genome of a N. pallida specimen with those of related species. The assembled chloroplast genome has a length of 162,381 bp with a typical quadripartite structure (LSC-IRA-SSC-IRB). The calculated GC content was 35.97%. However, this is variable between regions, with a higher GC content observed in the IRs. A total of 132 genes were annotated, of which 19 were duplicates and 22 contained at least one intron in their sequence. A substantial number of repetitive sequences of different types were identified in the assembled genome, predominantly tandem repeats (> 300). In particular, 142 microsatellites (SSR) markers were identified. The phylogenetic reconstruction showed that N. pallida grouped with the other Neltuma species and with Prosopis cineraria. The analysis of sequence divergence between the chloroplast genome sequences of N. pallida, N. juliflora, P. farcta and Strombocarpa tamarugo revealed a high degree of similarity. CONCLUSIONS: The N. pallida chloroplast genome was found to be similar to those of closely related species. With a size of 162,831 bp, it had the classical chloroplast quadripartite structure and GC content of 35.97%. Most of the 132 identified genes were protein-coding genes. Additionally, over 800 repetitive sequences were identified, including 142 SSR markers. In the phylogenetic analysis, N. pallida grouped with other Neltuma spp. and P. cineraria. Furthermore, N. pallida chloroplast was highly conserved when compared with genomes of closely related species. These findings can be of great potential for further diversity studies and genetic improvement of N. pallida.
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Fabaceae , Genoma del Cloroplasto , Prosopis , Humanos , Anotación de Secuencia Molecular , Prosopis/genética , Genoma del Cloroplasto/genética , Filogenia , Fabaceae/genéticaRESUMEN
Cuphea hookeriana Walp. is an ornamental plant belonging to the Lythraceae. In this study, we reported the complete chloroplast (cp) genome sequence here and analyzed the phylogenetic relationship among Lythraceae plants. The length of the cp genome was 158,999 bp, including a large single-copy (LSC, 89,311 bp) region and a small single-copy (SSC, 18,436 bp) region separated by a pair of inverted repeats (IRs, 25,626 bp). There were 72 unique protein-coding genes (PCGs), 30 transfer RNA (tRNA) genes, and four ribosomal RNA (rRNA) genes in the cp genome of C. hookeriana. A total of 223 simple sequence repeats (SSRs) and 34 long repeat sequences were identified. Phylogenetic analyses using maximum-likelihood (ML) revealed that C. hookeriana was close to C. hyssopifolia. In addition, the two Cuphea species were the sister group of Woodfordia fruticosa.
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BACKGROUND: Historical reconstructions within Podocarpaceae have provided valuable information to disentangle biogeographic scenarios that begun 65 Mya. However, early molecular phylogenies of Podocarpaceae failed to agree on the intergeneric relationships within the family. The aims of this study were to test whether plastome organization is stable within the genus Podocarpus, to estimate the selective regimes affecting plastome protein-coding genes, and to strengthen our understanding of the phylogenetic relationships and biogeographic history. METHODS AND RESULTS: We sequenced the plastomes of four South American species from Patagonia, southern Yungas, and Brazilian subtropical forests. We compared their plastomes to those published from Brazil, Africa, New Zealand, and Southeast Asia, along with representatives from other genera within Podocarpaceae as outgroups. The four newly sequenced plastomes ranged in size between 133,791 bp and 133,991 bp. Gene content and order among chloroplasts from South American, African and Asian Podocarpus were conserved and different from the plastome of P. totara, from New Zealand. Most genes showed substitution patterns consistent with a conservative selective regime. Phylogenies inferred from either complete sequences or protein coding regions were mostly congruent with previous studies, but showed earlier branching of P. salignus, P. totara and P. sellowii. CONCLUSIONS: Highly similar and conserved plastomes of African, South American and Asian species suggest that P. totara plastome should be revised and compared to other species from Oceanic distribution. Furthermore, given such structural conservation, we suggest plastome sequencing is not useful to test whether genomic order can be climatically or geologically structured.
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Cloroplastos , Genómica , Filogenia , Secuencia de Bases , BrasilRESUMEN
Chloroplast genomes are considered to be highly conserved. Nevertheless, differences in their sequences are an important source of phylogenetically informative data. Chloroplast genomes are increasingly applied in evolutionary studies of angiosperms, including Magnoliaceae. Recent studies have focused on resolving the previously debated classification of the family using a phylogenomic approach and chloroplast genome data. However, most Neotropical clades and recently described species have not yet been included in molecular studies. We performed sequencing, assembly, and annotation of 15 chloroplast genomes from Neotropical Magnoliaceae species. We compared the newly assembled chloroplast genomes with 22 chloroplast genomes from across the family, including representatives from each genus and section. Family-wide, the chloroplast genomes presented a length of about 160 kb. The gene content in all species was constant, with 145 genes. The intergenic regions showed a higher level of nucleotide diversity than the coding regions. Differences were higher among genera than within genera. The phylogenetic analysis in Magnolia showed two main clades and corroborated that the current infrageneric classification does not represent natural groups. Although chloroplast genomes are highly conserved in Magnoliaceae, the high level of diversity of the intergenic regions still resulted in an important source of phylogenetically informative data, even for closely related taxa.
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Sporadic rains in the Atacama Desert reveal a high biodiversity of plant species that only occur there. One of these rare species is the "Red añañuca" (Zephyranthes phycelloides), formerly known as Rhodophiala phycelloides. Many species of Zephyranthes in the Atacama Desert are dangerously threatened, due to massive extraction of bulbs and cutting of flowers. Therefore, studies of the biodiversity of these endemic species, which are essential for their conservation, should be conducted sooner rather than later. There are some chloroplast genomes available for Amaryllidaceae species, however there is no complete chloroplast genome available for any of the species of Zephyranthes subgenus Myostemma. The aim of the present work was to characterize and analyze the chloroplast of Z. phycelloides by NGS sequencing. The chloroplast genome of the Z. phycelloides consists of 158,107 bp, with typical quadripartite structures: a large single copy (LSC, 86,129 bp), a small single copy (SSC, 18,352 bp), and two inverted repeats (IR, 26,813 bp). One hundred thirty-seven genes were identified: 87 coding genes, 8 rRNA, 38 tRNA and 4 pseudogenes. The number of SSRs was 64 in Z. phycelloides and a total of 43 repeats were detected. The phylogenetic analysis of Z. phycelloides shows a distinct subclade with respect to Z. mesochloa. The average nucleotide variability (Pi) between Z. phycelloides and Z. mesochloa was of 0.02000, and seven loci with high variability were identified: psbA, trnSGCU-trnGUCC, trnDGUC-trnYGUA, trnLUAA-trnFGAA, rbcL, psbE-petL and ndhG-ndhI. The differences between the species are furthermore confirmed by the high amount of SNPs between these two species. Here, we report for the first time the complete cp genome of one species of the Zephyranthes subgenus Myostemma, which can be used for phylogenetic and population genomic studies.
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Here, we report the first complete chloroplast (cp) genome of Cinchona officinalis. This cp genome has a 156,984 bp in length with typical quadripartite structure, containing a large single copy (LSC) region (83,929 bp) and an 18,051 bp small single-copy (SSC) region, separated by two inverted repeat (IR) regions (27,502 bp). The total GC content was 37.75%. Quina tree chloroplast genome possesses 135 genes that consisted of 89 protein-coding genes, 37 tRNA, eight rRNA, and one pseudogene. Phylogenetic analysis showed that C. officinalis is sister to C. pubescens and sister to them is Isertia laevis; all belong to the Cinchonoideae sub-family.
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BACKGROUND: Brazil is exceptionally abundant in medicinal plant resources and has a rich ethnopharmacological history. Brazilian Pharmacopoeia (BP) acts as a national standard that regulates drug quality and has six published editions. Recent genomic approaches have led to a resurgence of interest in herbal drugs. The genomic data of plants has been used for pharmaceutical applications, protecting natural resources, and efficiently regulating the market. However, there are few genomic databases specifically for medicinal plants, and the establishment of a database that focuses on the herbs contained in the BP is urgently required. METHODS: The medicinal plant species included in each edition of the BP were analyzed to understand the evolution of the Brazilian herbal drugs. The data of 82 plants in the BP were collected and categorized into four sections: DNA barcodes, super-barcodes, genomes, and sequencing data. A typical web server architecture pattern was used to build the database and website. Furthermore, the cp-Gs of the Aloe genus in the database were analyzed as an illustration. RESULTS: A new database, the Brazilian Pharmacopoeia Genomic Database (BPGD) was constructed and is now publicly accessible. A BLAST server for species identification and sequence searching with the internal transcribed spacer 2 (ITS2), the intergenic region (psbA-trnH), and the chloroplast genome (cp-G) of Brazilian medicinal plants was also embedded in the BPGD. The database has 753 ITS2 of 76 species, 553 psbA-trnH and 190 genomes (whole genome and chloroplast genome) of 57 species. In addition, it contains 37 genome sequence data sets of 24 species and 616 transcriptome sequence data sets of 34 species and also includes 187 cp-Gs representing 57 medicinal species in the BP. Analyses of the six cp-Gs of three Aloe species identified the variable regions in the cp-Gs. These can be used to identify species and understand the intraspecific relationships. CONCLUSIONS: This study presents the first genomic database of medicinal plants listed in the latest BP. It serves as an efficient platform to obtain and analyze genomic data, accelerate studies regarding Brazilian medicinal plants and facilitate the rational development on their market regulation.
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MAIN CONCLUSION: The chloroplast genomes of Caesalpinia group species are structurally conserved, but sequence level variation is useful for both phylogenomic and population genetic analyses. Variation in chloroplast genomes (plastomes) has been an important source of information in plant biology. The Caesalpinia group has been used as a model in studies correlating ecological and genomic variables, yet its intergeneric and infrageneric relationships are not fully solved, despite densely sampled phylogenies including nuclear and plastid loci by Sanger sequencing. Here, we present the de novo assembly and characterization of plastomes from 13 species from the Caesalpinia group belonging to eight genera. A comparative analysis was carried out with 13 other plastomes previously available, totalizing 26 plastomes and representing 15 of the 26 known Caesalpinia group genera. All plastomes showed a conserved quadripartite structure and gene repertoire, except for the loss of four ndh genes in Erythrostemon gilliesii. Thirty polymorphic regions were identified for inter- or intrageneric analyses. The 26 aligned plastomes were used for phylogenetic reconstruction, revealing a well-resolved topology, and dividing the Caesalpinia group into two fully supported clades. Sixteen microsatellite (cpSSR) loci were selected from Cenostigma microphyllum for primer development and at least two were cross-amplified in different Leguminosae subfamilies by in vitro or in silico approaches. Four loci were used to assess the genetic diversity of C. microphyllum in the Brazilian Caatinga. Our results demonstrate the structural conservation of plastomes in the Caesalpinia group, offering insights into its systematics and evolution, and provides new genomic tools for future phylogenetic, population genetics, and phylogeographic studies.
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Caesalpinia , Genoma del Cloroplasto , Brasil , Caesalpinia/genética , Genética de Población , Genoma del Cloroplasto/genética , FilogeniaRESUMEN
The genus Isoëtes is globally distributed. Within the Neotropics, Isoëtes occurs in various habitats and ecosystems, making it an interesting case study to address phylogenetic and biogeographic questions. We sequenced and assembled plastomes and ribosomal DNA (rDNA) sequences to reconstruct phylogenetic relationships in Isoëtes from tropical regions in the Neotropics. The ploidy level of nine taxa was established to address the potential source of phylogenetic incongruence in the genus. Node ages were estimated using MCMCTree. The ancestral range estimates were conducted in BioGeoBEARS. Plastome-based phylogenies were congruent throughout distinct matrices and partition schemes, exhibiting high support for almost all nodes. Whereas, we found incongruences between the rDNA and plastome datasets. Chromosome counts identified three diploids, five tetraploids and one likely hexaploid among Neotropical species. Plastome-based node age estimates showed that the radiation of the crown Isoëtes group occurred at 20 Ma, with the diversification of the tropical American (TAA) clade taking place in the Pleistocene at 1.7 Ma. Ancestral range estimates showed that the ancestor of the TAA clade may have evolved first in the dry diagonal area in South America before reaching more humid regions. In addition, the colonization of the Brazilian semiarid region occurred three times, while the occupation of the Cerrado and Amazon regions occurred twice and once, respectively. Our study showed a large unobserved diversity within the genus in warm-dry regions in the Neotropics. Plastomes provided sufficient genomic information to establish a robust phylogenetic framework to answer evolutionary questions in Isoëtes from the Neotropics.
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Ecosistema , Genoma de Plastidios/genética , Genómica , Filogenia , Filogeografía , Plastidios/clasificación , Plastidios/genética , BrasilRESUMEN
The chloroplast genome of the Magnolia species from Central America has never been reported. With its local use for food flavoring, medicine, and wood, M. mexicana has been of good economic importance. In the present study, the complete chloroplast genome of M. mexicana was assembled via the genome skimming data. As a typical quadripartite structure, the plastome of M. mexicana with 159,906 bp in length includes two inverted repeats (26,554 bp) separated by a small single copy region (18,761 bp) as well as a large single copy region (88,037 bp). This chloroplast genome consists of 131 different genes, including 86 protein coding genes (CDS), eight rRNA genes, and 37 tRNA genes. The maximum likelihood phylogenetic analysis showed that M. mexicana from Central America was closely related to an evergreen species, M. odoratissima from East Asia.
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Chloroplast genomes (cpDNA) in angiosperms are usually highly conserved. Although rearrangements have been observed in some lineages, such as Passiflora, the mechanisms that lead to rearrangements are still poorly elucidated. In the present study, we obtained 20 new chloroplast genomes (18 species from the genus Passiflora, and Dilkea retusa and Mitostemma brevifilis from the family Passifloraceae) in order to investigate cpDNA evolutionary history in this group. Passiflora cpDNAs vary in size considerably, with â¼50 kb between shortest and longest. Large inverted repeat (IR) expansions were identified, and at the extreme opposite, the loss of an IR was detected for the first time in Passiflora, a rare event in angiosperms. The loss of an IR region was detected in Passiflora capsularis and Passiflora costaricensis, a species in which occasional biparental chloroplast inheritance has previously been reported. A repertory of rearrangements such as inversions and gene losses were detected, making Passiflora one of the few groups with complex chloroplast genome evolution. We also performed a phylogenomic study based on all the available cp genomes and our analysis implies that there is a need to reconsider the taxonomic classifications of some species in the group.
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ADN de Cloroplastos/química , Reordenamiento Génico , Genoma del Cloroplasto , Passiflora/genética , Filogenia , Secuencias Invertidas Repetidas , Passiflora/química , Passiflora/clasificaciónRESUMEN
BACKGROUND: Maize is one of the most important crops worldwide and has been a target of nuclear-based transformation biotechnology to improve it and satisfy the food demand of the ever-growing global population. However, the maize plastid transformation has not been accomplished due to the recalcitrant condition of the crop. RESULTS: In this study, we constructed two different vectors with homologous recombination sequences from maize (Zea mays var. LPC13) and grass (Bouteloua gracilis var. ex Steud) (pZmcpGFP and pBgcpGFP, respectively). Both vectors were designed to integrate into rrn23S/rrn16S from an inverted repeat region in the chloroplast genome. Moreover, the vector had the mgfp5 gene driven by Prrn, a leader sequence of the atpB gene and a terminator sequence from the rbcL gene. Also, constructs have an hph gene as a selection marker gene driven by Prrn, a leader sequence from rbcL gene and a terminator sequence from the rbcL gene. Explants of maize, tobacco and Escherichia coli cells were transformed with both vectors to evaluate the transitory expressionan exhibition of green and red fluorescent light under epifluorescence microscopy. These results showed that both vectors were expressed; the reporter gene in all three organisms confirmed the capacity of the vectors to express genes in the cell compartments. CONCLUSIONS: This paper is the first report of transient expression of GFP in maize embryos and offers new information for genetically improving recalcitrant crops; it also opens new possibilities for the improvement in maize chloroplast transformation with these vectors.
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Nicotiana/metabolismo , Cloroplastos/genética , Cloroplastos/metabolismo , Zea mays/genética , Proteínas Fluorescentes Verdes/metabolismo , Transformación Genética , Biotecnología , Reacción en Cadena de la Polimerasa , Plantas Modificadas Genéticamente , Plastidios/genética , Proteínas Fluorescentes Verdes/genética , Escherichia coli , Genoma del CloroplastoRESUMEN
DNA is one of the fastest growing tools in forensic sciences, increasing reliability in forensic reports and judgments. The use of DNA has increased in different areas of the forensic sciences, such as investigation of plant species, where plastid DNA has been used to elucidate and generate evidence in cases of traceability of genetically modified and controlled plants. Even with several advances and the practice of using DNA in forensic investigations, there are just few studies related to the identification of genetic tools for the characterization of drug and nondrug-types of Cannabis. Herein, the whole plastomes of two drug-type Cannabis are presented and have their structures compared with other Cannabis plastomes deposited in the GenBank, focusing in the forensic use of plastome sequences. The plastomes of Cannabis sativa "Brazuka" and of the hybrid Cannabis AK Royal Automatic presented general structure that does not differs from the reported for other C. sativa cultivars. A phylogenomic analyses grouped C. sativa "Brazuka" with the nondrug C. sativa cultivars, while the hybrid Cannabis AK Royal Automatic placed isolated, basal to this group. This suggests that the analysis of plastomes is useful toward genetic identification of hybrids in relation to C. sativa.
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Cannabis/genética , Genoma de Plastidios , Plastidios/genética , ADN de Plantas , Bases de Datos de Ácidos Nucleicos , Ciencias Forenses , Secuenciación de Nucleótidos de Alto Rendimiento , Filogenia , Análisis de Secuencia de ADNRESUMEN
Magnolia ofeliae A. Vázquez & Cuevas, a plant species endemic to south Jalisco, Mexico, is a critically endangered (CR) species based on the IUCN Red List. In this study, we assembled its complete chloroplast (cp) genome. The total genome size of M. ofeliae was 159,839 bp including four subregions: a large single-copy (LSC) region of 88,027 bp and a small single-copy (SSC) region of 18,752 bp separated by a pair of identical inverted repeat regions (IRs) of 26,530 bp each. The GC content of the cp genome of M. ofeliae is 39.3%. The cp genome encoded a set of 113 genes, containing 79 protein-coding genes, 30 tRNA genes, and four rRNA genes. Phylogenetic analysis results that M. ofeliae is a sister to all other magnolias in the subfamily Magnolioideae.
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The chloroplast genome of Tabebuia nodosa is described and characterized here. This species is endemic to the Chaco and the first species of Tabebuia to have its organelle genome sequenced, providing a genomic resource for phylogenetic inferences. The plastome of T. nodosa is 158,454 bp in length, with a large single-copy of 85,406 bp, a small single-copy of 12,785 bp, and inverted repeats of 30,116 bp each. It contains 131 genes, with 86 protein-coding genes, 37 tRNA, and 8 rRNA. Overall, the GC content is 38.2%. The T. nodosa plastome resembles the structural organization of plastomes commonly found in flowering plants, including those of other genera of Bignoniaceae. A phylogenetic analysis combining a subset of Bignoniaceae plastomes confirms the placement of T. nodosa within the Tabebuia alliance with maximum support.
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Chloroplast (cp) genome organization, gene order, and content have long been considered conserved among land plants. Despite that, the generation of thousands of complete plastomes through next-generation sequencing (NGS) has challenged their conserved nature. In this study, we analyze 11 new complete plastomes of Amphilophium (Bignonieae, Bignoniaceae), a diverse genus of Neotropical lianas, and that of Anemopaegma prostratum. We explored the structure and content of the assembled plastomes and performed comparative analyses within Amphilophium and among other plastomes available for Bignoniaceae. The overall gene content and orientation of plastomes is similar in all species studied. Plastomes are not conserved among Amphilophium, showing significant differences in length (155,262-164,786 bp), number of genes duplicated in the IRs (eight, 18, or 19), and location of the SC/IR boundaries (i.e., LSC/IRa junction between rps19 and rpl2 genes, within petD, or within petB). Length differences reflect expansions of the IRs and contractions of the LSC regions. The plastome of A. prostratum is 168,172 bp, includes 19 duplicated genes, and has the LSC/IRa boundary located within the petB gene. Amphilophium plastomes show high nucleotide diversity, with many hypervariable regions, and 16 genes with signatures of positive selection. Multiple SSRs and repeat regions were identified for Amphilophium and Anemopaegma prostratum. The differences in structure detected within Amphilophium plastomes in terms of LSC/IR and IR/SSC boundaries, number of duplicated genes, and genome sizes are mostly shared between taxa that belong to the same clade. Our results bring new insights into the evolution of plastomes at low taxonomic levels.