scholarly journals Genetic variability, cryptic species and phylogenetic relationship of six cyathostomin species based on mitochondrial and nuclear sequences

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mariana Louro ◽  
Tetiana A. Kuzmina ◽  
Christina M. Bredtmann ◽  
Irina Diekmann ◽  
Luís M. Madeira de Carvalho ◽  
...  

AbstractCyathostomins are important intestinal nematode parasites of equines and include 50 accepted species. Their taxonomy has been frequently revised and the presence of cryptic species suggested. Furthermore, usually molecular- and morphology-based phylogenetic analyses give divergent results. In this study, the nucleotide sequences of the nuclear second internal transcribed spacer (ITS-2) and the mitochondrial partial cytochrome c oxidase subunit I (COI) were determined for adults of six cyathostomin species (Coronocyclus coronatus, Coronocyclus labiatus, Cylicocyclus nassatus, Cylicostephanus calicatus, Cylicostephanus longibursatus, Cylicostephanus minutus) collected from different equine species within two geographic regions. Maximum likelihood trees were calculated for ITS-2, COI, and concatenated data. No obvious differentiation was observed between geographic regions or equine host species. As previously reported, Coronocyclus coronatus and Cylicostephanus calicatus revealed a close relationship. Cryptic species were detected in Cylicostephanus minutus and Cylicostephanus calicatus. Cylicocyclus nassatus and Coronocyclus labiatus showed diverse mitochondrial and nuclear haplotypes occurring in different combinations, while Cylicostephanus longibursatus was comparatively homogenous. In conclusion, a combined analysis of nuclear and mitochondrial haplotypes improved resolution of the phylogeny and should be applied to the remaining cyathostomin species and across additional equine host species and geographic regions.

Phytotaxa ◽  
2014 ◽  
Vol 172 (3) ◽  
pp. 235 ◽  
Author(s):  
Klára Řeháková ◽  
Jan Mareš ◽  
Alena Lukešová ◽  
Eliška Zapomělová ◽  
Kateřina Bernardová ◽  
...  

The taxonomy of cyanobacteria currently faces the challenge of overhauling the traditional system to better reflect the results of phylogenetic analyses. In the present study, we assessed the phylogenetic position, morphological variability, ability to produce the toxin nodularin, and source habitat of 17 benthic and soil isolates of Nodularia. A combined analysis of two loci (partial 16S rRNA gene and rbcLX region) confirmed the genus as a monophyletic unit and the close relationship of its members. However, the taxonomic resolution at the subgeneric level was extremely problematic. The phylogenetic clustering did not show any reasonable congruence with either morphological or ecological features commonly used to separate taxa in heterocytous cyanobacteria. Despite the near phylogenetic similarity of planktonic, benthic and soil Nodularia strains, we did not find any new nodularin-producing strains among the non-planktonic isolates. The relatively low variability in conserved molecular markers within the genus Nodularia exemplifies the limitations of the currently accepted taxonomic workflow and polyphasic approach. Elucidation of mechanisms that drive the phenotypic variability in such groups presents a major challenge in cyanobacterial research.


2019 ◽  
Vol 3 (6) ◽  
Author(s):  
Martijn J T N Timmermans ◽  
Sainab M Daghmoumi ◽  
Deborah Glass ◽  
Chris A Hamilton ◽  
Akito Y Kawahara ◽  
...  

Abstract Ambulycini are a cosmopolitan tribe of the moth family Sphingidae, comprised of 10 genera, 3 of which are found in tropical Asia, 4 in the Neotropics, 1 in Africa, 1 in the Middle East, and 1 restricted to the islands of New Caledonia. Recent phylogenetic analyses of the tribe have yielded conflicting results, and some have suggested a close relationship of the monobasic New Caledonian genus CompsulyxHolloway, 1979 to the Neotropical ones, despite being found on opposite sides of the Pacific Ocean. Here, we investigate relationships within the tribe using full mitochondrial genomes, mainly derived from dry-pinned museum collections material. Mitogenomic data were obtained for 19 species representing nine of the 10 Ambulycini genera. Phylogenetic trees are in agreement with a tropical Asian origin for the tribe. Furthermore, results indicate that the Neotropical genus Adhemarius Oiticica Filho, 1939 is paraphyletic and support the notion that OrectaRothschild & Jordan 1903 and TrogolegnumRothschild & Jordan, 1903 may need to be synonymized. Finally, in our analysis the Neotropical genera do not collectively form a monophyletic group, due to a clade comprising the New Caledonian genus Compsulyx and the African genus BatocnemaRothschild & Jordan, 1903 being placed as sister to the Neotropical genus ProtambulyxRothschild & Jordan, 1903. This finding implies a complex biogeographic history and suggests the evolution of the tribe involved at least two long-distance dispersal events.


Botany ◽  
2010 ◽  
Vol 88 (7) ◽  
pp. 675-684 ◽  
Author(s):  
A. Tsuneda ◽  
S. Hambleton ◽  
R. S. Currah

Cleistopycnidial ontogeny and sequences of nuclear internal transcribed spacers (ITS) and large subunits (LSU) were compared for five strains of Endoconidioma populi Tsuneda et al.: three from trembling aspen and two from alder. The cleistopycnidia of two of the aspen strains, including the type strain, were subglobose to flask-shaped (mostly 35–100 µm × 30–60 µm), and consisted solely of meristematic cells with thick cell walls that were heavily impregnated with melanin granules. Peridial cells were not visibly differentiated from locular cells and were also capable of forming endoconidia. Endoconidia were released from one to several sites of the cleistopycnidium by the dissolution of peridial cell wall. The alder strains shared these characteristics, except that their cleistopycnidia released both endoconidia and conidiogenous cells. Unlike those four strains, cleistopycnidia of the third aspen strain were cylindrical, often exceeding 500 µm in length, branched, and possessed a peridium of textura angularis that developed from short, determinate hyphae. Conidiogenous cells contained abundant lipid bodies that were not mobilized until the onset of endoconidiogenesis. The peridium at the basal area was prone to breakage by external forces, indicating that the individual cleistopycnidium, as a whole, functions as a dispersal unit. A small number of ITS nucleotide differences among strains corresponded to their observed morphological differences and host association. Phylogenetic analyses suggested a close relationship of E. populi with Hormonema carpetanum Bills, Peláez & Ruibal, and Coniozyma leucospermi (Crous & Denman) Crous.


2021 ◽  
Vol 168 (4) ◽  
Author(s):  
Abigail L. Mabey ◽  
Elahe Parvizi ◽  
Ceridwen I. Fraser

AbstractProtistan pathogens have been found to infect populations of some large brown macroalgae. Infection could reduce the ability of macroalgae to withstand hydrodynamic pressures through weakening tissues and reducing flexibility. Widespread mortality of macroalgae if disease outbreaks were to occur could have important flow-on consequences for biodiversity and ecosystem function. Recent discoveries of the protistan pathogen Maullinia infecting the ecologically keystone southern bull kelp Durvillaea in Chile, Australia, and on Marion Island, raise the possibility that this pathogen is dispersing across ocean basins with buoyant hosts. To determine whether Maullinia also infects southern bull kelp in New Zealand, samples of gall-like tissue from Durvillaea antarctica, D. poha, and D. willana were collected from intertidal sites, and genetic analyses (sequencing of partial 18S rRNA) carried out. Maullinia infections were detected in all three species of Durvillaea. Phylogenetic analyses show a close relationship of New Zealand Maullinia to M. braseltonii previously detected in Chile and on Marion Island. Based on its genetic similarity to distant lineages and its presence on buoyant hosts that have been shown to drift long distances at seas, we infer that Maullinia has dispersed across the Southern Ocean through rafting of infected bull kelp. Understanding the capacity of pathogens to disperse across oceans is critical part of forecasting and managing ecosystem responses to environmental change.


2000 ◽  
Vol 90 (10) ◽  
pp. 1098-1104 ◽  
Author(s):  
Juan J. Bernal ◽  
Ignacio Jiménez ◽  
Manuel Moreno ◽  
Melanie Hord ◽  
Carmen Rivera ◽  
...  

Chayote mosaic virus (ChMV) is a putative tymovirus isolated from chayote crops in Costa Rica. ChMV was characterized at the host range, serological, and molecular levels. ChMV was transmitted mechanically and induced disease symptoms mainly in Cucurbitaceae hosts. Asymptomatic infections were detected in other host families. Serologically, ChMV is related to the Andean potato latent virus (APLV) and the Eggplant mosaic virus (EMV), both members of the genus Tymovirus infecting solanaceous hosts in the Caribbean Basin and South America. The sequence of the genomic RNA of ChMV was determined and its genetic organization was typical of tymoviruses. Comparisons with other tymoviral sequences showed that ChMV was a new member of the genus Tymovirus. The phylogenetic analyses of the coat protein gene were consistent with serological comparisons and positioned ChMV within a cluster of tymoviruses infecting mainly cucurbit or solanaceous hosts, including APLV and EMV. Phylogenetic analyses of the replicase protein gene confirmed the close relationship of ChMV and EMV. Our results suggest that ChMV is related to two tymoviruses (APLV and EMV) of proximal geographical provenance but with different natural host ranges. ChMV is the first cucurbit-infecting tymovirus to be fully characterized at the genomic level.


Phytotaxa ◽  
2017 ◽  
Vol 292 (1) ◽  
pp. 35 ◽  
Author(s):  
TIAN-JING TONG ◽  
MING TANG ◽  
CHEN REN ◽  
QIN-ER YANG

We apply a multidisciplinary approach to settle the dispute over the generic affiliation of the Himalayan species Senecio kumaonensis (based on Cacalia penninervis). Some floral micromorphological characters of this species, including shape of anther bases, configuration of anther collars, and anther endothecial tissue cell wall thickenings, are confirmed to perfectly match those of Senecio and this has obviously resulted in the placement of the species within that genus. Chromosome counts indicate S. kumaonensis has 2n = 40, a number common to Senecio and Synotis but not occurring in Parasenecio (the correct generic name for the Asian species previously referred to Cacalia), which has 2n = 52, 58, and 60. The presence of six subterminal-centromeric (st) chromosomes in the karyotype of S. kumaonensis, however, lends strong support to the close relationship of this species to Synotis. Our phylogenetic analyses based on ITS/ ETS sequences also place S. kumaonensis in Synotis. In this species the anther tail feature, once deemed to be diagnostic for Synotis (anther bases in Synotis with sterile, tailed auricles vs. those in Senecio without such auricles, obtuse to sagittate), has an exception as evidenced from phylogeny. We therefore transfer S. kumaonensis to Synotis and, as the epithet “penninervis” has hitherto never been used in the genus, we propose the new combination Syn. penninervis for this species.


2020 ◽  
Vol 12 (7) ◽  
pp. 1060-1073 ◽  
Author(s):  
Dan Shen ◽  
Bo Gao ◽  
Csaba Miskey ◽  
Cai Chen ◽  
Yatong Sang ◽  
...  

Abstract Although the DD41D (named as Visitor, VS) family of Tc1/mariner transposons was discovered in Arthropods and Mollusca, the evolution profile of this family is still largely unknown. We found that VS is widespread in the animal kingdom, including 140 species of 18 orders in invertebrates and 30 species of 12 orders in vertebrates, and one land plant species. Our data revealed multiple horizontal transfer events in both invertebrates and vertebrates and invasion into multiple lineages of mammals, including Chiroptera (seven species), Dasyuromorphia/Marsupialia (one species), Didelphimorphia/Marsupialia (one species), Diprotodontia/Marsupialia (two species), and Primates (one species). Phylogenetic analysis revealed a close relationship of VSs to DD37D/maT and DD34D/mariner and confirmed that VSs with the DD40D signature identified previously are not a distinct family but originated from DD41D/VS. Age analysis revealed that the most recent invasion of VSs was found in ray-finned fishes and a toad, followed by relatively young invasions in bats and marsupials, whereas VSs in mammals, jawless fishes, and lizards were mainly represented by ancient copies, suggesting old age. Phylogenetic analyses and comparison of pairwise distances between VSs and recombination-activating gene 1 (RAG1) support horizontal transfer events of VSs in vertebrates. The intact VSs from bats were nonfunctional as determined by the transposition activity assay. Some vertebrate lineages and species were identified as the hot hosts of Tc1/mariner transposons. Overall, our study presents the evolution profile of VSs and suggests that VSs play roles in diversifying and shaping the genomes of diverse animal lineages.


2018 ◽  
Vol 94 ◽  
Author(s):  
H.-X. Chen ◽  
L.-P. Zhang ◽  
L. Li

Abstract The genus Megalobatrachonema is a rare group of nematode parasites within Ascaridida. The systematic status of Megalobatrachonema in the superfamily Cosmocercoidea (Ascaridida) has long been controversial. The relationship of Megalobatrachonema and Chabaudgolvania remains unsolved. In the present study, a new species of Megalobatrachonema, M. hainanensis sp. nov., was described based on specimens collected in Amolops hainanensis (Boulenger) and Hylarana spinulosa (Smith) (Amphibia: Anura) from Hainan Island, China. The large ribosomal DNA (28S) and internal transcribed spacer (ITS1-5.8S-ITS2) were also sequenced for molecular identification and phylogenetic study. Phylogenetic analyses using maximum likelihood (ML) inference and Bayesian inference (BI) based on 28S and ITS1 sequence data, respectively, supported that Megalobatrachonema is a member of the family Kathlaniidae. In addition, the genetic comparison and phylogenetic results based on ITS1 sequence data also supported that the genus Chabaudgolvania should be considered as a synonym of Megalobatrachonema.


Nematology ◽  
2010 ◽  
Vol 12 (3) ◽  
pp. 429-451 ◽  
Author(s):  
Juan Navas-Cortés ◽  
Blanca Landa ◽  
Nicola Vovlas ◽  
Gracia Liébanas ◽  
Pablo Castillo ◽  
...  

AbstractA new amphimictic species, Pratylenchus hispaniensis n. sp., parasitising the roots of gum cistus in Andújar (Jaén), southern Spain, is described. The new species is characterised by the presence of numerous males and by the female having a lip region with three annuli, a divided face, a robust stylet (14.5-17.0 μm) with rounded knobs, lateral fields with four lines, V = 80-84, a round spermatheca full of sperm, well developed post-vulval uterine sac and an obliquely truncate tail with irregularly annulated terminus. Morphologically this species is related to P. bhatti, P. kralli, P. mediterraneus, P. pseudofallax and P. thornei. A phenetic study of the 25 most useful diagnostic morphological and allometric characters for Pratylenchus species was done using multivariate factor and linear discriminant analyses. In the factor analysis the first seven factors accounted for 71.1% of the total variance of the characters selected. These factors were related to female tail, pharyngeal overlap, reproductive behaviour, stylet length, L/post-vulval uterine sac ratio, body length and number of lip annuli. Discriminant analysis differentiated Pratylenchus spp. from the three valid species of Zygotylenchus. The results of the phylogenetic analysis based on sequences of the D2-D3 expansion regions of 28S, partial 18S and ITS rRNA genes confirmed the close relationship of P. hispaniensis n. sp. with P. mediterraneus and inferred molecular affinity with P. brzeskii, P. neglectus and P. thornei, in spite of variation in the position of P. hispaniensis n. sp. in the clades. Additional phylogenetic analyses based on the same sets of sequences for P. hispaniensis n. sp., Zygotylenchus guevarai and other Pratylenchidae indicated that Pratylenchus includes several paraphyletic lineages; however, likelihood tests did not reject monophyly of the genus. The inclusion of Pratylenchus, Zygotylenchus, Hirschmanniella, Nacobbus and Apratylenchus in Pratylenchidae was supported.


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