Molecular Phylogenetic Research Articles

La anatomía de la raíz como evidencia filogenética para los helechos Cheilanthoides (Pteridaceae)

Background and aims: To our hypothesis on the evolutionary relationships of Cheilanthoid ferns, based on molecular data and partially on morphological and reproductive data, we add here a study of root anatomy in the genera of the subfamily occurring in South America. M&M: Root characters were analyzed anatomically in 48 South American species representing the 12 genera of Cheilanthoideae occurring in South America. Techniques of plant histology were used for anatomical analysis and tissue characterization. Characters with possible diagnostic value were identified and mapped on a molecular phylogeny of Cheilanthoideae based on three plastidial markers (rbcL, trnL-F and rps4). Results: The character "type of root cortex" showed a distribution of states that fit to the major clades or genera in the phylogeny of the subfamily. The homogeneous cortex state was plesiomorphic for Cheilanthoideae, whereas the heterogeneous bark state was acquired by some genera of the hemionitoid clade: Hemionitis and the genera of the Adiantopsis-Doryopteris clade (except Mineirella). In addition, we discuss the role of different tissues in the root mechanics of this group. Conclusions: The character "type of root cortex" could contribute to the characterization of genera and the generic assignment of confusing species in the classification of Cheilanthoideae. However, the complete resolution of the relationship of hemionitds clade in the global phylogeny of the subfamily is necessary.

Phylogenetic reconstruction of Didymocarpus and related genera in Gesneriaceae with establishment of two new genera

AbstractThe genus Didymocarpus Wall. is a core group of the subfamily Didymocarpoideae in Gesneriaceae with a complex taxonomic history. It has long been controversial to delimit Didymocarpus and its allies. We conducted phylogenetic reconstructions with high‐density sampling of Didymocarpus and related genera by using four nuclear ribosomal DNAs (external transcribed spacer [ETS], internal transcribed spacer [ITS], 18S, 26S) and five chloroplast DNAs (atpB‐rbcL, rpl16, rps16, trnH‐psbA, and trnL‐F). The results indicated that neither Didymocarpus nor Allocheilos are monophyletic. Based on molecular phylogenetic and morphological analyses, we delimitated the range of the Didymocarpus sensu stricto (s. str.) with two‐section division, and established a new genus Palmatiboea for species originally placed in Didymocarpus. This genus is remarkably distinguished from Didymocarpus s. str. not only in molecular phylogeny and morphology but also in its specific geographic distribution, in that it is found only in Southeast China. In addition, we proposed a new monotypic genus Hequnia for Allocheilos guangxiensis that is completely isolated in phylogeny, consistent with a range of remarkably distinctive morphological characteristics. Our results clarify the systematics of Didymocarpus and the delimitation between it and related genera with establishment of two new genera.

Positive Selection of Mitochondrial cytochrome b Gene in the Marine Bivalve Keenocardium buelowi (Bivalvia, Cardiidae)

The mitochondrial genome provides valuable data for phylogenetic analysis and evolutionary research. In this study, we sequenced, assembled, and annotated the mitochondrial genome of Keenocardium buelowi using the Illumina platform. The genome spanned 16,967 bp and included 13 protein-coding genes (PCGs), two ribosomal RNAs, and 22 transfer RNAs. All PCGs utilized standard ATN start codons and TAN stop codons. The phylogenetic tree based on maximum likelihood and Bayesian inference analyses revealed Clinocardiinae as the sister group to Trachycardiinae, with the estimated divergence time being 44.5 million years ago (MYA) between K. buelowi and Vasticardium flavum. Notably, the cytochrome b gene (cob) exhibited a positive selection signal. Our findings provide valuable insights into the evolutionary history and molecular phylogeny of K. buelowi.

Description of three widespread new Peronospora species parasitising Caryophyllales

Downy mildews are cosmopolitan obligate biotrophic parasites of flowering plants. They are fungus-like eukaryotes of the kingdom Straminipila, and most species are highly specialised, often parasitising only a single host species. Due to the prevalence of a broad species concept before the advent of molecular phylogenetics and the paucity of differentiating characteristics in some groups, many widespread species are still undescribed. This is also the case for some downy mildews in the clade containing the type species of Peronospora, Peronospora rumicis. Spurred by the discovery of the undescribed species parasitising Rumex acetosa at the Blávík research station in East Iceland, three new widespread species of Peronospora are introduced in this article: Peronospora blauvikensis parasitic to Rumex acetosa, P. boylei parasitic to Rumex thyrsiflorus, and P. spergulariae parasitic to Spergula marina. As the species are morphologically highly similar, a set of diagnostic bases is given for each species, allowing a quick identification via molecular barcoding.

Molecular characterization of Hyalomma scupense and its vector-borne pathogen Theileria annulata in Ksar El Boukhari (Medea, Algeria)

This study analyzed the molecular and phylogenetic profiles of Theileria annulata, the causative agent of tropical theileriosis in cattle, and its tick vector Hyalomma scupense in Algeria. Forty H. scupense ticks were collected in Medea, with 5 testing positive for Theileria spp. based on partial COXIII gene sequences. Positive ticks were further analyzed using COX1 and 12S rRNA genes. Two novel H. scupense 12S rRNA haplotypes and one novel COX1 haplotype were identified. One T. annulata haplotype previously reported in Algerian cattle was detected. This represents the first molecular characterization of T. annulata from H. scupense ticks in Algeria, providing insights into the genetic diversity of the parasite vector in this region. Overall, the study reveals new haplotypes for both the tick vector and parasite, furthering our understanding of their molecular profiles and phylogenetics in Algeria.

Sampling poorly studied lineages improves resolution in mitogenome-based phylogenies of leafhoppers (Hemiptera: Cicadellidae)

Abstract Cicadellidae (leafhoppers) may be the most diverse and abundant insect herbivores in terrestrial ecosystems worldwide, with more than 23,000 described species in 20 extant subfamilies. Although prior studies have supported the monophyly of most recognized subfamilies, relationships among these groups remain inconsistently resolved and previous molecular phylogenies have failed to support the monophyly of a few subfamilies. To help address this deficiency, we combined 24 new complete mitogenomes representing 6 previously unsequenced subfamilies and 13 tribes with previously available data to create a dataset of 79 cicadellid taxa representing 16 subfamilies for phylogenetic analysis. The new analyses confirm that leafhopper mitochondrial genomes are highly conservative in overall structure, with only a few rare rearrangements of tRNAs. All phylogenetic analyses consistently supported the monophyly of previously recognized cicadellid tribes for which more than 1 representative was included and all of the included subfamilies were also consistently recovered as monophyletic with the exception of Aphrodinae and Eurymelinae. Bayesian inference and Maximum Likelihood analyses with site-homogeneous models are only slightly affected by nucleotide compositional heterogeneity and yield more stable phylogenetic relationships of family-group taxa than analyses with a heterogeneous-site mixture model using PhyloBayes. Molecular divergence time estimates indicate that the main lineages of Cicadellidae, most corresponding to recognized subfamilies, diverged during the Cretaceous period (93–121 Mya).

DNA barcoding: An effective molecular tool for species identification, molecular authentication and phylogeny studies in plant science research

DNA barcoding is a technique for identifying specimens using brief, standardised DNA segments. In a variety of fields, including phylogeny, ecology, population genetics and biodiversity, DNA barcoding has become a successful method for precisely distinguishing species. The method is straightforward, efficient in both time and money and accurate. The key to successful DNA barcoding is choosing the right DNA marker. Since the idea of a quick approach for species identification was first put up in 2003, the scientific community has been keen to realise the potential of DNA barcodes. Cytochrome c oxidase, I (COI) region of the mitochondrial genome is mostly recognised as a standard barcoding region in animals. Later, rbcL + matK pairing, with a 70 % discriminating efficiency, was suggested by the Plant Working Group (PWG) of the Consortium for the Barcoding of Life (CBOL) as the standard barcode in plants. Three conditions must be met for a gene region to be an efficient DNA barcode: it must have sufficient species-level genetic divergence and variability, it must have conserved flanking regions for the widest taxonomic use and for generating universal PCR primers and it should be long enough to facilitate current capability for sequencing and extracting DNA. Different combinations of plastid coding, non-coding and nuclear markers are utilised as supplemental markers to boost the degree of plant species differentiation. The reliability of different barcodes in distinguishing species varies among different groups of plants. As DNA barcoding approaches its twentieth anniversary, technologies are still being developed that make use of this resource, which is constantly expanding in a variety of biological disciplines. Plant DNA barcoding, which became a scientific advance during the last ten years, is frequently employed as a taxonomical aid in identifying species. It is a way of choosing genetic loci that identifies and distinguishes an organism's membership from specific species, variations or even intervarieties. It varies from molecular phylogeny, which identifies an unknown sample from an existing classification rather than identifying patterns of association.

First report of acifer group of the subgenus Tripodura Townes (Diptera: Chironomidae: Polypedilum) from India, with a new species and updated world checklist

A new species of the acifer group of the subgenus Tripodura and genus Polypedilum Kieffer is described on the basis of adult male. The acifer species group is recorded firstly from India. The molecular barcoding of the new species is provided. Moreover, molecular phylogeny of all available species of the subgenus Tripodura, along with an Indian key based on adult males of this subgenus have been designed here. Additionally, a world checklist of the subgenus Tripodura has also been furnished in this study.

Genetic Diversity and Relationship of Native Phalaenopsis Orchids: A Case Study of Indonesian Archipelago

The native Phalaenopsis is valuable germplasm for future orchid breeding programs and for its conservation because it provides many beneficial traits or genes. This study aimed to determine and analyze the molecular diversity and phylogeny of Indonesian native Phalaenopsis by a DNA barcoding (matK) marker. A total of 19 samples of Phalaenopsis orchids were used in this study. All leaf samples of orchid were extracted and purified using a commercial DNA isolation kit from Geneaid Biotech Ltd., Taiwan (GP100). The DNAs were then amplified by specific matK primers: Forward (5’-CGTACAGTACTTTTGTGTTTACGAG-3’) and Reverse (5’-ACCCAGTCCATCTGGAAATCTTGGTTC-3’). The DNA targets or products (matK) were purified and sequenced by the Sanger-bidirectional method at 1st Base Ltd., Malaysia. Before further analysis, the matK sequences of Phalaenopsis were edited, reconstructed, and aligned with the assistance of Clustal W in the MEGA 11 software. Its genetic diversity was determined using the nucleotide diversity index (π%), and the phylogenetic analysis was performed using the maximum likelihood (ML) method with a statistical bootstrap. The phylogenetic relationship was also assessed using principal component analysis (PCA). Based on this marker, the native Phalaenopsis has a high genetic diversity (π% = 1.70). In addition, the phylogenetic analysis revealed that this germplasm was separated into seven clades, where P. pantherina has the closest relation to P. cornu-cervi and P. gigantea. Conversely, the highest genetic distance was to P. amabilis from South Kalimantan and to P. celebensis from Sulawesi, at a coefficient divergence of 0.084. Our findings provide an essential foundation for supporting future orchid breeding practices, including conservation, on local and global scales.

Discosia brasiliensis causing Discosia leaf blight on tea plant (Camellia sinensis) in China

Tea (Camellia sinensis), a perennial evergreen shrub, is one of the most important cash crops in China. Tea leaves with symptoms of wilt disease was observed in Fengqing County, Lincang City, Yunnan Province, China. Large irregular jujube-red necrotic spots appeared on the leaves of tea plants, and the lesions with grayish white edge were accompanied by a certain degree of shrinkage. In the tea garden planting base, the natural disease incidence reached 40%–50 %, which significantly affects the yield of tea. One putative pathogen was isolated from three symptomatic tea plant leaves and was identified as Discosia brasiliensis using morphology and molecular phylogeny of multi-loci (ITS, LSU, tub, rpb2) sequence data. Using D. brasiliensis strains for artificial inoculation assay on the tea plant leaves, leaf atrophy symptom in leaves which is similar to those observed in the tea planting base, and the putative pathogen was re-isolated to fulfill Koch's postulates. This is the first report of wilt disease caused by Discosia brasiliensis in China.

The transcriptomic landscape of spinal V1 interneurons reveals a role for En1 in specific elements of motor output.

Neural circuits in the spinal cord are composed of diverse sets of interneurons that play crucial roles in shaping motor output. Despite progress in revealing the cellular architecture of the spinal cord, the extent of cell type heterogeneity within interneuron populations remains unclear. Here, we present a single-nucleus transcriptomic atlas of spinal V1 interneurons across postnatal development. We find that the core molecular taxonomy distinguishing neonatal V1 interneurons perdures into adulthood, suggesting conservation of function across development. Moreover, we identify a key role for En1, a transcription factor that marks the V1 population, in specifying one unique subset of V1Pou6f2 interneurons. Loss of En1 selectively disrupts the frequency of rhythmic locomotor output but does not disrupt flexion/extension limb movement. Beyond serving as a molecular resource for this neuronal population, our study highlights how deep neuronal profiling provides an entry point for functional studies of specialized cell types in motor output.

Morphology and molecular phylogeny of four epibiotic ciliates (Ciliophora, Peritrichia) from farmed red swamp crayfish Procambarus clarkii Girard, 1852, with notes on the geographic distributions of related taxa

Aquaculture of red swamp crayfish Procambarus clarkii is an emerging farming industry in China. As shown recently, one of the most significant diseases affecting the red swamp crayfish is caused by overabundance of epibiotic peritrichs, a group of ciliated protists that are commonly found living as epibionts on aquatic animals. Nevertheless, few studies focusing on this issue have been performed. As part of a faunal study carried out in the Lake Weishan Wetland, China, four colonial sessilid peritrichs, namely Epicarchesium granulatum, Epistylis bimarginata, Epistylis semiciculus, and Zoothamnium procerius, attached to P. clarkii are documented. For each species, redescriptions and improved diagnoses are supplied. As a further aid to identification, 14 new rDNA sequences of these four and a closely related species were obtained. In addition, as an aid for future studies on epibiotic ciliates, we supply a list and information about recent integrative studies that document the geographic distributions of related taxa.

Ultrastructure and molecular phylogeny of Mesodinium annulatum sp. nov. (Mesodiniidae, Cyclotrichiida), a new member of the Mesodinium rubrum / Mesodinium major complex

The species complex <i>Mesodinium rubrum</i> / major, common red tide-forming ciliates, has been intensively studied with regards to its ecological roles in global marine ecosystems and the evolutionary aspects of its “stolen” organelles (kleptoplasty and karyoklepty). Nonetheless, the taxonomy of the species within the complex remains unclear. A new marine Mesodinium species isolated from Gomso Bay, Korea, was cultivated under mixotrophic conditions by providing <i>Teleaulax amphioxeia</i>, a red cryptomonad, as prey. Cells of the new isolate consisted of two portions separated by two types of polykinetids. The number of polykinetid associated with the equatorial ciliary belt was approximately 38, and each consisting of two rows of up to 18 alternating kinetosomes each. There was an equal number of cirral polykinetids, each consisting of 16 kinetosomes organized into four longitudinal rows having five, five, four, and two kinetosomes, respectively (in anti-clockwise direction). The two kinds of kinetids and their associated microtubules and fibers were structurally similar to those of <i>M. rubrum</i> from Denmark. However, the Korean <i>Mesodinium</i> species was characterized by its broad posterior portion, 20–22 tentacles, and a cytopharyngeal annulus. Molecular phylogeny based on internal transcribed spacer sequences placed the Korean isolate in clade B of the <i>M. rubrum</i> / major species complex, rather than in clade F representing the neotype of <i>M. rubrum</i>. Based on morphological, ultrastructural, and molecular data, we propose the Korean strain as a new marine <i>Mesodinium</i> species, <i>M. annulatum</i>.

Molecular taxonomy of gastric carcinoma

Molecular taxonomy of gastric carcinoma

The evolution of tenascins

BackgroundThe evolution of extracellular matrix is tightly linked to the evolution of organogenesis in metazoans. Tenascins are extracellular matrix glycoproteins of chordates that participate in integrin-signaling and morphogenetic events. Single tenascins are encoded by invertebrate chordates, and multiple tenascin paralogs are found in vertebrates (designated tenascin-C, tenascin-R, tenascin-W and tenascin-X) yet, overall, the evolution of this family has remained unclear.ResultsThis study examines the genomes of hemichordates, cephalochordates, tunicates, agnathans, cartilaginous fishes, lobe-finned fishes, ray-finned fishes and representative tetrapods to identify predicted tenascin proteins. We comprehensively assess their evolutionary relationships by sequence conservation, molecular phylogeny and examination of conservation of synteny of the encoding genes. The resulting new evolutionary model posits the origin of tenascin in an ancestral chordate, with tenascin-C-like and tenascin-R-like paralogs emerging after a whole genome duplication event in an ancestral vertebrate. Tenascin-X appeared following a second round of whole genome duplication in an ancestral gnathostome, most likely from duplication of the gene encoding the tenascin-R homolog. The fourth gene, encoding tenascin-W (also known as tenascin-N), apparently arose from a local duplication of tenascin-R.ConclusionsThe diversity of tenascin paralogs observed in agnathans and gnathostomes has evolved through selective retention of novel genes that arose from a combination of whole genome and local duplication events. The evolutionary appearance of specific tenascin paralogs coincides with the appearance of vertebrate-specific cell and tissue types where the paralogs are abundantly expressed, such as the endocranium and facial skeleton (tenascin-C), an expanded central nervous system (tenascin-R), and bone (tenascin-W).

Shining new light on naupliar eyes: A novel molecular phylogeny for Pleuromamma (Family: Metridinidae) and the characterization of luciferase and opsin expression

Pleuromamma (Giesbrecht, 1898) is a cosmopolitan genus of metridinid copepods, with species that perform remarkable diel vertical migrations (DVM) and emit a bioluminescent secretion when disturbed that varies both spectrally and kinetically. Copepod bioluminescence is autogenic and uses luciferase enzymes that catalyze a luciferin, coelenterazine, to produce light. Pleuromamma possess naupliar eyes, relatively simple photosensitive structures used for many visually-guided behaviors. Yet the fundamental molecular unit for vision, the opsin protein, has not been previously described for the family. The light producers and detectors are important to study because DVM is a behavior that mediates significant active elemental fluxes between the upper ocean and midwaters across vast stretches of oceanic habitat, and DVM is guided by visual behaviors, with animals tracking an isolume. Here we provide the first fully resolved molecular phylogeny for Pleuromamma (Family: Metridinidae) and describe the luciferase and opsin gene diversity and expression using de novo assembled transcriptomes. We successfully sequenced and assembled transcriptomes for 10 of 11 described species of Pleuromamma as well as two other metridinid species: Metridia longa and Gaussia princeps. In all species, we obtained coding sequences of one putative rhabdomeric middle wavelength sensitive visual opsin gene, as well as several non-visual opsins – a c-type pteropsin and a tetra-opsin type peropsin. Furthermore, Pleuromamma express luciferases from each of two main evolutionary clades (Luc1 and Luc2), and a single paralog (Luc2a) dominates expression throughout the group. The variation in luciferase number, sequence, and expression among species could lead to different spectral and kinetic properties of bioluminescence and aid in congener recognition.

Comprehensive molecular phylogeny and diversification of snappers (Actinopterygii: Perciformes: Lutjanidae) from the Odisha coast, Bay of Bengal, India: taxonomy and distribution

Comprehensive molecular phylogeny and diversification of snappers (Actinopterygii: Perciformes: Lutjanidae) from the Odisha coast, Bay of Bengal, India: taxonomy and distribution

Cortinarius steglichii: a taxonomical and chemical novelty from Chile

The new species Cortinarius steglichii is described from Chilean Nothofagus forest based on morphological and microscopical attributes, molecular phylogeny, and chemical analysis of secondary metabolites. C. steglichii is characterized by abundant, long, ramified cystidia on the lamellar edges and stipe apex, further by a deep violet color reaction after treatment with KOH. As responsible secondary metabolite for the cytoplasmatic color reaction of cystidia and some hyphae, the new diterpenoid steglichon (1) could be recognized, showing also remarkable antibacterial and anticancer activity. Phylogenetic analyses (ITS, LSU, RPB1) confirm the close relationship to species of the Cortinarius dulciolens group.

Integrative taxonomy and biogeography of the genus Oxytrechus (Coleoptera: Carabidae: Trechini) in the tropical alpine ecosystem of Ecuadorian Andes, with the description of six new species

Summary This study presents a taxonomic revision of the species of the ground beetle genus Oxytrechus Jeannel, 1927 that inhabit the superpáramo of the Andes of Ecuador, which constitutes the uppermost zone of the tropical alpine ecosystem, above 4200 m. Sixteen species, displayed in three clades, were recorded in this environment, six of which are described as new: Oxytrechus antisanae n. sp. (Mt Antisana), O. giachinoi n. sp. (Mt Illiniza), O. hamatus n. sp. (Mt Atacazo and Pichincha), O. prunai n. sp. (Mt Guamaní), O. reflexus n. sp. (Mt Illiniza and Mt Corazón), and O. robbiolai n. sp. (Mt Pichincha). New distributional data are presented for O. chioriae Quéinnec & Ollivier, 2019, O. lallemandi Jeannel, 1927, O. moreti Mateu, 1988 and O. zoiai Casale & Sciaky, 1985. The first molecular phylogeny of the group, based on fragments of four mitochondrial and two nuclear genes, is given. Dichotomous identification keys are provided to the species groups and the included species. Based on systematic sampling, Oxytrechus exhibits the highest degree of microendemism among páramo ground beetles. No species has been found in more than two sky islands, and half of the species recorded in the superpáramo are single-mountain endemics. As regards their conservation status, eight species (two thirds) can be classified as vulnerable or endangered, due to a mix of low abundance, narrow distribution range, microendemism, limited ecological tolerance, habitat destruction and effects of climate change.

There and back again: molecular phylogenetics of the Brazilian endemic Psyllocarpus (Rubiaceae: Spermacoceae) supports a circumscription of the genus based on its original concept

There and back again: molecular phylogenetics of the Brazilian endemic <i>Psyllocarpus</i> (Rubiaceae: Spermacoceae) supports a circumscription of the genus based on its original concept