Plants

Premise of study"El Chango" is a recently discovered quarry that contains extremely well preserved fossils. The Cenomanian age of the locality corresponds to a time when the global flora was transitioning from gymnosperm- to angiosperm-dominated, yet conifers predominate in this locality. These fossils thus provide a rare opportunity to understand the replacement of conifers by angiosperms as the dominant group of plants. MethodsWe collected material from El Chango in annual expeditions (2010 to 2014). We selected the three most abundant and best preserved conifer morphotypes and conducted a total-evidence (i.e.,, including molecular and morphological data) phylogenetic analysis of a sample of 72 extant conifer species plus the three fossils. We use these results to inform our taxonomic decisions. ResultsWe obtained four equally most-parsimonious trees (consistency index = 44.1%, retention index = 78.8%). Despite ambiguous relationships among some extant taxa, the three fossil conifers had the same phylogenetic position in all four most-parsimonious trees; we describe these species as new: Sequoiadendron helicalancifolium sp. nov. (Cupressaceae), and Microcachrys rhomboidea sp. nov. and Dacrydium bifoliosus sp. nov (Podocarpaceae). The ecosystem is interpreted as a coastal humid mixed forest. ConclusionsOur findings contribute to the understanding of Cenomanian equatorial regions, and support the hypothesis of a geographically and ecologically structured "rise of angiosperms", with conifers remaining dominant in brackish-water and angiosperms becoming dominant in freshwater-ecosystems. These fossils fill in gaps in the evolutionary history of lineages like Microcachrys, which we demonstrate occurred in the Northern hemisphere before becoming restricted to its current range (Tasmania).

Taxanes form effective anticancer agents, which are found in the leaves and barks of the yew tree (Taxus L.). Taxol(R) (also known as paclitaxel), 10-diacetylbacatin III, 10-deacetyltaxol III, baccatin III and cephalommanine are anti-neoplastic taxanes used for cancer treatment. Due to the high demand of taxanes, it is of great pharmaceutical interest to investigate unexplored to date population diversity. In this context, three peripheral Greek Taxus baccata L. populations (Mt Cholomon, Mt Olympus and Mt Vourinos) were investigated to identify the extent and structure of their genetic (based on microsatellite markers), epigenetic (based on methylation sensitive amplified markers) and chemodiversity (based on liquid chromatography mass spectrometry) profiles. Results showed that the concentration of taxanes varied considerably in relation to population and harvest season. The main taxane in T. baccata needles was 10-deacetylbacatin III (DAB), with concentrations ranging from 267.8 (Mt Vourinos) to 517.6 (Mt Olympus) mg kg-1 dw. Besides metabolite variation, notable levels of genetic diversity and significant population differentiation were revealed. These results, in conjunction to the high levels of total methylation found in all populations, indicate their potential adaptability under climatic change. The findings of this study pave the way for prospective breeding and conservation strategies of these important Taxus baccata L. populations for artificial selection of highly producing taxane trees and protection of local germplasm.

BackgroundThe saffron-producing Crocus sativus and its wild relative C. cartwrightianus are key species for understanding genetic evolution in this genus. Molecular-cytogenetic methods, especially fluorescent in situ hybridization (FISH), are essential for exploring the genetic relationships in this genus. Yet, preparing high-quality chromosomes for FISH analysis across Crocus species remains difficult. A standardized protocol for achieving clear and well-separated mitotic chromosomes is still lacking. This study assesses the effectiveness of four chromosome fixation methods for optimal chromosome spread preparation in Crocus. Root tips of different Crocus species were treated with four chromosome preparation methods namely hydroxyurea-colchicine (HC), nitrous oxide (NO), hydroxyquinoline (HQ), and ice water (IW) pretreatments to investigate their effectiveness in producing high-quality mitotic chromosome spreads. Metaphases obtained by the four methods were analyzed to assess their quality and metaphase index. ResultsEvaluation of 22,507 nuclei allowed us to confidently recommend a protocol for Crocus chromosome preparation. Among the methods, ice water pretreatment yielded the highest metaphase index (2.05%), more than doubling the results of HC (1.08%), NO (1.15%), and HQ (1.16%). Ice water-treated chromosomes exhibited better chromosome morphology, with relatively proper size, and non-overlapping chromosomes that were optimal for FISH analysis. Ice water pretreatment was also applied to C. cartwrightianus, the diploid progenitor of C. sativus, where it demonstrated similar efficacy. DAPI staining of chromosomes in both species allowed for clear visualization of intercalary and terminal heterochromatin. FISH analysis using 18S-5.8S-25S and 5S rDNA probes confirmed the utility of IW-prepared chromosome spreads for cytogenetic studies. ConclusionsWe strongly recommend ice water pretreatment as a suitable and effective method for obtaining many metaphase spreads of high-quality in C. sativus and related species, particularly for applications involving a detailed cytogenetic analysis.

Qualitative differences in the nrDNA ITS and ETS sequences in the total sample were determined to allow identification of the following groups of samples: H. mantegazzianum, H. cf. sosnowskyi, H. cf. mantegazzianum and H. cf. sosnowskyi x H. cf. mantegazzianum among other representatives of the Heracleum genus presented in the genetic databases. The study revealed the absence of correlation between a sample type in the group H. mantegazzianum, H. cf. sosnowskyi, H. cf. mantegazzianum and H. cf. sosnowskyi x H. cf. mantegazzianum and qualitative transformations in the ITS and ETS sequences. The qualitative analysis of the rbcL, matK, rps16 intron, intergenic spacers psbA-trnH, trnQ-rps16, rps16-trnK and rpl32-trnL cpDNA sequences for the samples identified as Heracleum mantegazzianum, H. cf. sosnowskyi, H. cf. mantegazzianum and H. cf. sosnowskyi x H. cf. mantegazzianum demonstrated no correlation between them as well.

The genus Passiflora L. (Passifloraceae) is widely distributed, primarily in the Neotropics, and comprises over 500 species divided into four main subgenera. The subgenus Passiflora is the most economically relevant and has a basic chromosome number of x = 9, with P. foetida L. being the sole species in the subgenus having a chromosome number of n = 10. However, P. foetida exhibits substantial morphological variation among its varieties, and recently, two of these varieties were reclassified as Passiflora vesicaria L. and P. vesicaria var. galapagensis. This study aimed to cytogenetically characterise both species by estimating genome sizes using flow cytometry, mapping heterochromatic regions by CMA/DAPI staining, and identifying 5S and 35S ribosomal DNA sites using fluorescent in situ hybridization (FISH). The genome sizes were similar across the three accessions analyzed, varying from 2C = 1.00 {+/-} 0.03 pg for P. vesicaria var. galapagensis to 2C = 1.16 {+/-} 0.01 pg for P. vesicaria, indicating small genomes. All three accessions showed 2n = 20, confirming the count for P. foetida and revealing the chromosome numbers of the two P. vesicaria accessions for the first time. Six CMA+ bands were observed in P. foetida, four in P. vesicaria var. galapagensis, and two in P. vesicaria, all co-localised with the 35S rDNA sites. FISH with 5S and 35S rDNA showed six pericentromeric 35S sites of different intensities in P. foetida and four interstitial 5S sites, with one individual having only two interstitial 5S sites, demonstrating a polymorphism at the intrapopulation level not yet recorded for the genus or the species. Passiflora vesicaria exhibited four 35S sites also pericentromeric, as well as two 5S sites, while P. vesicaria var. galapagensis presented four pericentromeric 35S sites and two 5S sites. Therefore, despite these species having the same chromosome number (n = 10) and similar genome sizes, there are karyotypic variations in the number of CMA+ bands and rDNA sites, allowing their discrimination.

The sesquiterpene phytolactone derived from Artemisia annua, artemisinin is associated with a variety of novel biological properties, such as immunoregulatory and anticancer effects, and therapeutic applications, apart from its main function as an antimalarial drug. Emerging from the fact that artemisinin production in planta occurs in trace amounts and its compartmentalized synthesis, the irregular agricultural supply often results in market fluctuations and reductions in artemisinin inventory. Further improvement in artemisinin production calls for approaches that act in a supplementary manner, filling the agricultural production gap. Here we investigated the elicitation efficiency of ultraviolet B (UV-B) and dimethyl sulfoxide (DMSO) independently on a low-artemisinin producing (LAP) chemotype of the species A. annua. The exposure of cell suspension cultures to short-term UV-B radiation and DMSO treatment did not result in significant changes in artemisinin yield. The lack of stimulation has been associated with: (i) the general lack of cytodifferentiation of cell cultures; (ii) negative feedback regulation of artemisinin biosynthesis; and (iii) artemisinin sequestration by cellular detoxification. Further molecular analysis revealed the repression of key genes ADS, DBR2 and ALDH1 which affected artemisinin synthesis. This study provides insights into the complexity of stress-induced responses of A. annua cell suspension cultures in relation to metabolic processes (transportation, accumulation and degradation of secondary products) which are important for artemisinin formation.

As part of the work, the key factors influencing the growth and development of Artemisia salsoloides culture have been studied, and nutrient media have been developed and optimized for plant conservation. The optimal medium for the cultivation of A. salsoloides is MS + 2 mg/L MT. Viable suspensions were obtained. The MS nutrient medium and the BM1k nutrient medium developed by us are suitable for wormwood callusogenesis. The growth curves of cell suspensions have a standard S-shaped curve. In the A. salsoloides plants we studied, key genes for the synthesis of artemisinin-like compounds (ADS, CYP71AV1, DBR2) were found, except for the CPR gene.

We report the complete chloroplast sequences of two varieties of Theobroma cacao collected in the Bolivian Amazonia using Next-Generation Sequencing. Comparisons made between these two chloroplast genomes and the Belizean reference plastid genome identified 19 and 22 nucleotide variants. The phylogenetic analysis reported three main T. cacao clades belonging to the Forastero, Criollo and Trinitario groups. The Bolivian Native Cacao varieties were located inside the Trinitario group forming their unique branch. The Bolivian Native Cacao branch reveals a possible new subpopulation different from the well-characterized T. cacao subpopulations. The phylogenetic trees showed that the relationships among the T. cacao varieties were consistent with their geographical locations placing the Cacao Center of Origin in Western Amazon. The data presented here will contribute to the usage of ultrabarcoding to distinguish different T. cacao varieties and to identify native cacaos from introduced cacaos. Thus helping in the conservation of local native varieties of T. cacao.

The complete nucleotide sequence of the Akebia trifoliata chloroplast (cp) genome was reported and characterized in this study. The cp genome is a closed circular molecule of 157 949 bp, composed of a pair of IR regions of 26 149 bp, one LSC region of 86 595 bp, and one SSC region of 19 056 bp. The GC contents of the LSC, SSC, and IR regions, and the whole cp genome are 37.11%, 33.62%, 43.08% and 38.66%, respectively. The cp genome contains 130 predicted functional genes, including 85 PCGs of 79 107 bp, 37 tRNA and 8 rRNA genes of 11 851 bp. 168 SSRs and 23 long repeats were identified in the cp genome. The results revealed that 21 891 codons characterize the coding capacity of 85 protein-coding genes in Akebia trifoliata, 10.84% and 1.20% of the codons coded for leucine and cysteine respectively. The usage of the start codon exhibited no bias in the A. trifoliata cp genome. Phylogenetic analysis suggest that A. trifoliata is most closely related to S. japonica, which then formed a cluster with N. dormestica and M. saniculifolia to form subgroup of Ranunculales. Our study provides information on mangrove plant species in coastal intertidal zones.

The taxonomy and nomenclature of the type materials potentially attributable to the three recognized annual species of the grass genus Brachypodium (B. distachyon, B. stacei, B. hybridum) have been investigated through statistical discriminant analysis of twelve quantitative morphological traits in eight herbarium types corresponding to heterotypic synonyms and newly designated types of each species, along with the lectotype and the epitype of B. distachyon and the holotypes of B. stacei and B. hybridum, plus 50 additional representative specimens of the currently recognized taxa, and through a comprehensive nomenclatural review. The possible taxonomic assignments of types to these species and the nomenclatural priority of Brachypodium distachyon and ten related names, B. hybridum, B. macrostachyum, B. megastachyum, B. stacei, Bromus pentastachyos, Festuca monostachyos, F. rigida, Trachynia platystachya, Triticum schimperi, and T. subtile, have been discussed. Lectotypes are designated for Festuca monostachyos, F. rigida, Triticum schimperi, and T. subtile. Based on our taxonomic and nomenclatural study, the names Festuca monostachyos and Triticum subtile can be considered conspecific and heterotypic synonyms of the Linnaean name Bromus distachyos ({equiv} Brachypodium distachyon). Furthermore, the names Brachypodium macrostachyum, Brachypodium megastachyum, Bromus pentastachyos, Festuca rigida, and Brachypodium distachyon var. platystachyon ({equiv} Trachynia platystachya) are conspecific with Brachypodium hybridum, and Triticum schimperi is conspecific with Brachypodium stacei. Since the names B. hybridum and B. stacei are in common use, but both are later heterotypic synonyms, respectively, of the names of the species with which they are conspecific, a proposal for the conservation of these two names is necessary. On the other hand, the application of the names Bromus pauper, Brachypodium geniculatum, Festuca pseudistachya, Bromus paradoxus, and Triticum flabellatum is uncertain, and as such, they are treated as nomen ambiguum. Finally, Festuca ciliata and Triticum asperum are two illegitimate names, according to Art. 52.1 of the Shenzhen Code, while Triticum brevisetum is a new synonym of Brachypodium retusum. A lectotype for the name T. brevisetum is also selected and designated in this paper.

Herbaria harbor a tremendous amount of plant specimens that are rarely used for plant systematic studies. The main reason is the difficulty to extract a decent quantity of good quality DNA from the preserved plant material. While the extraction of ancient DNA in animals is well established, studies including old plant material are still underrepresented. In our study we compared the standard Qiagen DNeasy Plant Mini Kit and a specific PTB-DTT protocol on two different plant genera (Xanthium L. and Salix L.). The included herbarium material covered about two centuries of plant collections. A selected subset of samples was used for a standard library preparation as well as a target enrichment approach. The results revealed that PTB-PTT resulted in higher quantity and quality regarding DNA yield. For relatively recent herbarium specimens, and despite the lower overall yield of DNA, the Qiagen Kit resulted in better sequencing results regarding the number of filtered and mapped reads. We were able to successfully sequence a sample from 1820 and conclude that it is possible to include old herbarium specimens in NGS approaches. This opens a treasure box for phylogenomic research.

Kenaf (Hibiscus cannabinus), a native warm-seasonal crop in Africa, is being considered for genetic improvement for local bast fiber production. To expedite its genetic improvement through breeding, kenaf genotypes from Ghana were assessed for genomic diversity regarding their chromosomal composition and ploidy levels. To gain insight into the repetitive DNA fractions in kenaf, the organization of 5S and 35S rRNA genes, as well as telomeric signal patterns were studied by a molecular cytogenetic approach. Using multi-color fluorescent in situ hybridization, distinct rDNA loci and Arabidopsis-type telomeres were revealed. The 5S rRNA genes were conserved in kenaf and localized in interstitial regions of two chromosomes across all accessions. The 35S rRNA genes were variable across the kenaf accessions and localized at sub-terminal ends and rarely interstitially in eight or six chromosome arms. Telomeric signals were observed at terminal ends of all chromosomes, with smaller signals also interstitially. The chromosome configuration of Ghana kenaf accessions was confirmed to be 2n=2x=36, each. We discuss the chromosomal variability and the likely genomic instability in the kenaf breeding lines from Ghana. To our knowledge, this is the first report on molecular cytogenetics on kenaf and thus, provides valuable insights into the genome of kenaf that will be useful for breeding. Additionally, this study provides a basis for further studies to analyze the repetitive DNA sequences and develop reference karyotypes to reveal genetic and evolutionary relationships between cultivated and wild Hibiscus species.

Accurate identification is crucial for conserving species, especially in regions such as the Western Ghats, where trade poses a significant threat to endangered and threatened forest species. Traditional morphology-based identification can be challenging and time-consuming, leading to inaccuracies, especially with similar-looking species or dried specimens. Therefore, DNA barcoding offers a potent solution for precise species identification to address illicit trade and address impactful conservation measures. DNA barcoding is a taxonomic technique that uses standardized short DNA sequences to differentiate and classify species. This approach is especially valuable when morphological characteristics alone are insufficient for accurate species identification. In this study, we focused on the development of a DNA barcoding system for the efficient and accurate identification of threatened and endangered important forest species of Western Ghats Karnataka. To develop the DNA barcoding system, a multilocus approach utilizing sixteen standard DNA barcoding markers was used. A total of 47 threatened and endangered forest species from the Western Ghats were selected for this study. Using a larger number of markers to develop DNA barcodes led to the most precise species identification rates. Moreover, the wide availability of DNA barcode databases allows for quick and accurate species identification. In our study, we observed the highest amplification rates for rbcL1 (40 species), psbtrnH2 (36 species), and PsbA-trnH1 (33 species). DNA amplification varied from 11.76% to 94.11%. Notably, the highest DNA amplification rates were detected for A. wightii (94.11%) and A. hondala (92.34%), both of which belong to the Arecaceae and Passifloraceae families, respectively. Sequencing success rates ranged from 37.5% to 100%. This study will aid in the development of a database of available threatened forest species in western Ghats Karnataka and other regions.

The genus Boechera, a prominent member of the tribe Boechereae within the family Brassicaceae, has emerged as an exceptional model for apomixis research, owing to its unique evolutionary, reproductive, and genomic characteristics. With over 480 genetically distinct taxa and a distribution spanning North America, Greenland, and parts of Asia, Boechera exemplifies remarkable ecological and genetic diversity. A hallmark of the genus is its high frequency of gametophytic apomixis, including diplospory and apospory, which, combined with hybridization, drive genetic innovation and environmental adaptability. Moreover, Boechera is notable for its diploid expression of apomixis, independent of polyploidy, providing an unparalleled system for dissecting asexual reproduction. Genomic adaptations, such as heterochromatic supernumerary chromosomes, further highlight its evolutionary complexity. Recent advances, including the discovery of critical regulatory genes like APOLLO and UPGRADE2, have deepened our understanding of the genetic basis of apomixis. These insights position Boechera as a cornerstone for elucidating apomictic pathways and leveraging these mechanisms for crop improvement. The genus not only enhances our understanding of apomixis but also offers transformative potential for agriculture.

Tea plant (Camellia sinensis) is an economically essential crop in China, Japan and other countries. The present study reports the meiotic behavior, including microsporogenesis of the Fudingdabai cultivar in Camellia sinensis var. sinensis. Most of the investigated pollen mother cells undergo normal meiosis processes. In contrast, a few of the pollen mother cells showed some abnormal phenomena such as cytomixis, monovalent, laggard chromosomes, unsynchronized division, micronucleus, and so on. Among which, spontaneous cytomixis is the most common phenomenon, which mainly occurred in early prophase I but also in meiosis II. Other abnormal phenomena were less than cytomixis. The results of this study laid a foundation for exploring the meiosis and cytogenetics study of the tea plants.

Hemp 7152, a sterile herbarium plot voucher of a shrub from a rare type of deciduous forest in the Usambara Mts, Tanzania was tentatively identified using morphology as a new species of Vepris (Rutaceae). To gain further support for its placement its chemistry was investigated. The compounds isolated from Hemp 7152 were four quinoline alkaloids, kokusaginine (1), N-methylplaty-desminium ion (9), ribalinium ion (10), and isoplatydesmine (11), and seven acridone alkaloids, arborinine (2) 1,2,3-trimethoxy-N-methylacridone (3), 1,2,3,5-tetramethoxy-N-methylacridone (4), 1,3-dimethoxy-N-methylacridone (5) and toddaliopsis A (6), evoxanthine (7) and tecleanthine (8). In addition, lupeol and ferulic acid were isolated from this plant. The combination of quinoline and acridone alkaloids is restricted to the Rutaceae family, confirming beyond reasonable doubt the placement of this material in the Rutaceae. Within Rutaceae in tropical Africa, only the genus Vepris is unarmed, with trifoliolate leaves. Using an identification key, and herbarium specimen matching, Hemp 7152 was morphologically placed as close to Vepris uguenensis, sharing xerophytic characters unusual in the genus. The species are geographically close, occurring in adjoining mountains in northern Tanzania. However, Vepris uguenensis contains 13 alkaloids which are not present in Hemp 7152, nor in any other species of Vepris that has been studied, supporting species recognition for Hemp 7152 which is formally named as Vepris hemp, morphologically characterised, illustrated and assessed as Critically Endangered using the IUCN 2012 standard. The new species appears restricted to an almost extinct type of deciduous forest, characterised in this paper.

The species-rich genus Inga (Leguminosae) presents ca. 300 species widespread throughout the Neotropics and is recognized by its recent and rapid diversification. Forty-eight species of Inga are endemic of the Brazilian Atlantic Forest. Among them, Inga subnuda, with two subspecies: subsp. subnuda, which occurs from the state of Paraiba to Rio de Janeiro; and subsp. luschnathiana, which occurs from Espirito Santo to the state of Santa Catarina. Both subspecies occur in sympatry in the southeastern region and share floral and leaf characters, which hampers the morphological delimitation. The co-occurrence of Inga vera subsp. affinis. with both I. subnuda subspecies results in intermediate morphologies between I. vera subsp. affinis and I. subnuda subsp. luschnathiana, making the distinction between the latter species even harder. We sampled 94 individuals from 8 natural populations and evaluated morphological characters previously described as distinctive among the subspecies of I. subnuda in addition to others not measured yet. We used 84 plastid (trnD-trnT spacer) and 58 nuclear (ITS 1 and 2) sequences to characterize the phylogenetic relationships between the taxa. The results obtained point out I. subnuda subsp. subnuda as a more structured taxon in relation to the other subspecies, whilst I. subnuda subsp. luschnathiana and I. vera subsp. affinis constituted a cohesive group. The apportionment of haplotypes differed between the markers used, thus evincing a retention of ancestral polymorphism between the subspecies, given their recent diversification. This paper explores different lines of evidence, thus contributing to the delimitation of these species. Demographic and biogeographic scenarios are also discussed. A new status of for the taxon currently circumscribed as Inga subnuda subsp. luschnathiana is suggested.

BackgroundThe widespread use of conventional pesticides to control plant fungal and bacterial pathogens poses significant risks to human health and the environment, and there is an urgent need for safer and more sustainable alternatives in agricultural management. Studies have shown that plant extracts can be effective in controlling plant diseases either by directly targeting the pathogens or by reinforcing the host plants own defenses. Here, we examined the potential of ethanolic extracts from forest tree species eastern hemlock, English oak, eastern red cedar and red pine for their antibacterial activity against Pseudomonas syringae pv. tomato (Pst) strain DC3000 and the ability of these forestry by-products to trigger effective defense responses in the model plant Arabidopsis thaliana. ResultsThe four tree extracts exhibited direct toxic effects against Pst DC3000, as notably observed for the English oak extract inhibiting bacterial growth and showing bactericidal activity at relatively low concentrations. Using an Arabidopsis line expressing reporter protein {beta}-glucuronidase under the control of a salicylic acid-inducible pathogenesis-related protein gene promoter, the extracts were shown also to induce defense-related genes expression in leaf tissue. RT-qPCR assays with DNA primers for different gene markers further confirmed this conclusion and highlighted gene-inducing effects for the tree extracts triggering, at different rates, the expression of salicylic acid- and oxidative stress-responsive genes. The extracts direct antibacterial effects, combined with their defense gene-inducing effects in planta, resulted in a strong host plant-protecting effect against Pst DC3000 associated with bacterial growth rates reduced by [~]75 to 98% seven days post-infection, depending on the extract. ConclusionsThese findings show the effectiveness of tree extracts as eventual plant protectants against the plant bacterial pathogen Pst. In a broader perspective, they suggest the potential of these forestry by-products as a source of bioactive compounds useful in plant protection and as a sustainable, eco-friendly alternative to conventional synthetic pesticides for the management of economically important plant pathogens.

Studies that optimize the haploid technique in the removal of maize lines are necessary. Between the stages that mostly requires attention and it is directly related to the success of the technology is the correctly separation of induced haploids and diploids. Morphological markers are commonly used but have strong influence of the environment, and laboratory methods have been developed and may be more efficient. Thus, the objective was to study the use of the anatomical analysis tool, through the analysis of young maize leaf for use as the indirect markers in the identification of ploidys. The hybrids were crossed with the KEMS haploid inducer. The seeds crossed, were selected according to the R-navajo marker and submitted to two different protocols of chromosome duplication. Plants that survived to the duplication protocols were acclimated in greenhouse and then transferred to the field. After the self-polinization of the DH0 plants, the DH1 seeds were taken to the field, divided into treatments according to the parentals and duplication protocols. At the vegetative stage V4 of the plants, leaf tissue samples were collected to the evaluation of the amount of DNA and identification of ploidys and anatomical analysis. The nuclear DNA review of each sample was performed for the comparison in histograms of the position of G1 peak to the G1 peak of the internal or external reference standard. A high accuracy came to validate an anatomical tool, through the variables studied in this work, as a marker in the differentiation of ploidis in maize plants, and it can be used in selection programs. The anatomy made in some letters is a non-destructible technique and, together with a flow cytometry technique, can be used as an indirect method in haploid cutting programs at the initial stage of the identification of seedlings.

BackgroundVaccinium is an economically important genus of berry crops in the family Ericaceae. Given the numerous hybridizations and polyploidization events among Vaccinium species, the taxonomy of this genus has remained uncertain and the subject of long debate. Therefore, the availability of more genomic resources for Vaccinium can provide useful tools for phylogenetic resolution, species identification, authentication of berry food products, and a framework for genetic engineering. ResultsIn this study, we assembled five Vaccinium chloroplast sequences representing the following berry types: northern highbush blueberry (V. corymbosum), southern highbush blueberry (V. corymbosum hybrids), rabbiteye blueberry (V. virgatum), lowbush blueberry (V. angustifolium), and bilberry (V. myrtillus). Two complete plastid genomes were achieved using long-read PacBio sequencing, while three draft sequences were obtained using short-read Illumina sequencing. Comparative analyses also included other previously available Vaccinium chloroplast sequences, especially the commercially important species V. macrocarpon (cranberry). The Vaccinium chloroplast genomes exhibited a circular quadripartite structure, with an overall highly conserved synteny and sequence identity among them. Despite their high similarity, we identified some polymorphic regions in terms of expansion/contraction of inverted repeats, gene copy number variation, simple sequence repeats, and single nucleotide polymorphisms. Phylogenetic analysis revealed multiple origins of highbush blueberry plastomes, likely due to the hybridization events during northern and southern highbush blueberry domestication. ConclusionsOur results enrich the genomic data availability for new Vaccinium species by sequencing and assembling the chloroplast DNA of major economically important berry types. Additional whole plastome analyses including more samples and wild species will be useful to obtain a refined knowledge of the maternal breeding history of blueberries and increase phylogenetic resolution at low taxonomic levels.