Dataset Information

Taxonomic and molecular identification of bakernema, criconema, hemicriconemoides, ogma and xenocriconemella species (nematoda: criconematidae).

ABSTRACT: Populations of Bakernema inaequale, C. petasum, C. sphagni, C. mutabile, Ogma octangulare, Xenocriconemella macrodora and Hemicriconemoides chitwoodi were identified and re-described from different geographical areas in the continental United States and molecularly characterized. Two new species of spine nematodes Criconema arkaense n. sp. from Washington County and Lee County, Arkansas and Criconema warrenense n. sp from Warren, Bradley County, Arkansas are also described and named. Criconema arkaense is characterize by having a conspicuous lip region offset from the body with two annuli, short rounded tail with a thin cuticular sheath and subterminal anus. Criconema warrenense n. sp. has two lip region annuli about the same width, first annulus directed posteriorly, separated by a narrow neck annulus and a short conoid tail, unilobed non-folded annulus. The molecular characterization of Criconema arkaense and Criconema warrenense using ITS1 rDNA gene sequence and the molecular phylogenetic relationships of these new species along with the known spines nematodes are provided.

SUBMITTER: Cordero MA

PROVIDER: S-EPMC3592369 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature

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Taxonomic and molecular identification of bakernema, criconema, hemicriconemoides, ogma and xenocriconemella species (nematoda: criconematidae).

Cordero Marco A MA Robbins Robert T RT Szalanski Allen L AL

Journal of nematology 20121201 4

Populations of Bakernema inaequale, C. petasum, C. sphagni, C. mutabile, Ogma octangulare, Xenocriconemella macrodora and Hemicriconemoides chitwoodi were identified and re-described from different geographical areas in the continental United States and molecularly characterized. Two new species of spine nematodes Criconema arkaense n. sp. from Washington County and Lee County, Arkansas and Criconema warrenense n. sp from Warren, Bradley County, Arkansas are also described and named. Criconema a ...[more]

PMID: 23482683

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Project description:The family Criconematidae is a remarkable group of nematodes, containing roughly 600 nominal root-ectoparasitic species, of which many species are known to be significant agricultural pests. Strikingly, our phylogenetic analyses based on 18S, D2-D3 of 28S rRNA, and COI mtDNA sequences of criconematid species, supported by tree topology tests (SH and AU tests), revealed that almost all studied genera, including Criconema, Ogma, Crossonema, Discocriconema, Hemicriconemoides, Criconemoides, Mesocriconema, and Lobocriconema, are not monophyletic groups, a finding that is partly contrary to those of previous studies on these groups. Our results suggest that key morphological characters used in the classification of Criconematidae are the consequence of convergent evolution. It is clear from our studies that the species status of at least 40 sequences of criconematid species from GenBank must be either revised or reconsidered, with analyses based on a polyphasic approach that includes different tree- and distance-based molecular species-delimitation methods (bPTP, GMYC, ABGD1, and ABGD2). Our studies found the ABGD2 output of the automatic barcode method to agree remarkably well with established species delimitations, while in general, the four species-delimitation results corresponding to three barcode regions forwarded significantly more putative species compared to those originally considered. This study also characterised for the first time the populations of Criconemoides myungsugae and Discocriconemella hensungica associated with Vietnamese ginseng, one of the most precious and rare ginseng varieties in the world. Although these populations are morphologically in agreement with the original descriptions of C. myungsugae and D. hengsungica, their molecular data display notable variations compared to the sequences deposited in GenBank. These species demonstrate clearly the immense molecular variations that can be observed in several species of the family Criconematidae.

Project description:Mesocriconema abolafiai n. sp. is described by morphological, morphometric, and molecular approaches. The new species is characterized by a body slightly curved with 402 to 612 μm length, 90 to 113 cuticular body annuli with smooth to irregular margins lacking of crenation with not more than one anastomoses, lip region not offset, small flattened submedian lobes, stylet robust (52.8-60.0 µm) with well-developed knobs, open vulva with simple anterior lip, straight vagina, filled spermatheca with globular sperms, presence of males, and conical-acute tail with last annulus bilobed or rounded. Discussions are made on the characterization of M. abolafiai n. sp. from the most closely related species, M. ozarkiense, and several other species having similar tail shape. Furthermore, results of phylogenetic analyses inferred from D2 to D3 expansion fragments of 28S rRNA, 18S rRNA, and ITS rRNA gene sequences revealed the phylogenetic position of the new species within representatives of Criconematidae and supported morphological justifications for considering this population from Iran as a new species in the genus Mesocriconema.Mesocriconema abolafiai n. sp. is described by morphological, morphometric, and molecular approaches. The new species is characterized by a body slightly curved with 402 to 612 μm length, 90 to 113 cuticular body annuli with smooth to irregular margins lacking of crenation with not more than one anastomoses, lip region not offset, small flattened submedian lobes, stylet robust (52.8-60.0 µm) with well-developed knobs, open vulva with simple anterior lip, straight vagina, filled spermatheca with globular sperms, presence of males, and conical-acute tail with last annulus bilobed or rounded. Discussions are made on the characterization of M. abolafiai n. sp. from the most closely related species, M. ozarkiense, and several other species having similar tail shape. Furthermore, results of phylogenetic analyses inferred from D2 to D3 expansion fragments of 28S rRNA, 18S rRNA, and ITS rRNA gene sequences revealed the phylogenetic position of the new species within representatives of Criconematidae and supported morphological justifications for considering this population from Iran as a new species in the genus Mesocriconema.

Project description:In Winter 2016, root and soil samples were collected from the rhizosphere soil at 10 to 15?cm depth of turfgrass, in the yard of a complex of houses in Caxias, a region near Lisbon, Portugal. The grass (dominated by tall fescue) showed yellow patches, stunting, and poor growth. Several specimens of a ring nematode (50-60 nematodes/100?ml soil) were recovered from soil and identified as Mesocriconema xenoplax (peach ring nematode) based on morphological and morphometrical analysis of females. The observed morphological features were with previous descriptions. Species identification was confirmed through sequencing of the fragment spanning D2/D3 domain of the 28S rDNA gene. Phylogenetic analysis revealed that the Portuguese isolate grouped with M. xenoplax isolates (98% similarity), supporting its identification as M. xenoplax. This is the first report of M. xenoplax from turfgrass in Portugal and in Europe contributing with additional information on the distribution of this phytoparasite.In Winter 2016, root and soil samples were collected from the rhizosphere soil at 10 to 15?cm depth of turfgrass, in the yard of a complex of houses in Caxias, a region near Lisbon, Portugal. The grass (dominated by tall fescue) showed yellow patches, stunting, and poor growth. Several specimens of a ring nematode (50-60 nematodes/100?ml soil) were recovered from soil and identified as Mesocriconema xenoplax (peach ring nematode) based on morphological and morphometrical analysis of females. The observed morphological features were with previous descriptions. Species identification was confirmed through sequencing of the fragment spanning D2/D3 domain of the 28S rDNA gene. Phylogenetic analysis revealed that the Portuguese isolate grouped with M. xenoplax isolates (98% similarity), supporting its identification as M. xenoplax. This is the first report of M. xenoplax from turfgrass in Portugal and in Europe contributing with additional information on the distribution of this phytoparasite.

Project description:BackgroundThe genus Marshallagia (Family Haemonchidae, subfamily Ostertagiinae) contains multiple species of nematodes parasitising the abomasum (or duodenum) of ruminants, in particular of Caprinae. Male specimens have been described to be polymorphic with the frequent/major morphotype initially described in the genus Marshallagia while the minor/rare morphotype was initially often placed in the genus Grossospicularia. Due to common morphological features, certain pairs of morphotypes were suggested to belong to the same species such as Marshallagia marshalli/M. occidentalis. However, molecular evidence to confirm these pairs of morphotypes belonging to the same species is missing.MethodsIn the present study, Marshallagia sp. were collected from domestic sheep in Uzbekistan. Male specimens were morphologically described with particular emphasis on the structure of the bursa copulatrix. After DNA isolation from morphologically identified specimens, PCRs targeting the ribosomal internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (cox1) regions were conducted. After Sanger sequencing, maximum likelihood phylogenetic analyses and pairwise identities between sequences were calculated.ResultsThe major morphotypes of M. marshalli, M. schumakovitschi and M. uzbekistanica and the minor morphotypes M. occidentalis, M. trifida and M. sogdiana were identified and their morphology was documented in detail. ITS2 sequences showed little variation and did not allow diagnosing species. In contrast, phylogenetic analysis of cox1 sequences identified highly supported clusters and verified that M. marshalli, M. occidentalis and M. uzbekistanica are different morphotypes of the species M. marshalli while M. schumakovitschi and M. trifida represent distinct morphotypes of M. trifida. For M. sogdiana no corresponding major morphotype could be identified in the present study. Due to a large barcoding gap, comparison of cox1 sequences in terms of percent identity was sufficient to reliably assign the sequences to a particular species without phylogenetic analysis.ConclusionsThe data presented here create a framework that will allow the classification of other members of the genus in the future and underline that parallel morphological and molecular analysis of specimens is crucial to improve the taxonomy of polymorphic species.

Dataset Information

Taxonomic and molecular identification of bakernema, criconema, hemicriconemoides, ogma and xenocriconemella species (nematoda: criconematidae).

Publications

Taxonomic and molecular identification of bakernema, criconema, hemicriconemoides, ogma and xenocriconemella species (nematoda: criconematidae).

Similar Datasets

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