Characterization of a species-specific satellite DNA from the entomopathogenic nematode Steinernema carpocapsae.
ABSTRACT An HaeIII satellite DNA family has been cloned from the entomopathogenic nematode Steinernema carpocapsae. This repeated sequence appears to be an unusually abundant satellite DNA, since it constitutes about 62% of the S. carpocapsae genome. The nucleotide sequences of 13 monomers have been determined. This satellite DNA family is represented by two sub-families: one with monomeric units of 170 bp and the other with monomeric units of 182 bp. These monomers are quite homogeneous in sequence, showing an average intermonomer variability of 6% from the consensus sequence. These results suggest that some homogenizing mechanism is acting to maintain the homogeneity of this satellite DNA. After hybridization with the genomic DNA of several other Steinernema species, this DNA sequence appears to be specific to the S. carpocapsae genome. Therefore, the species specificity and the high copy number of the HaeIII satellite DNA sequence should provide a rapid and powerful tool which could contribute to the identification of Steinernema species.
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ABSTRACT: Received 2001-01-19; accepted 2001-06-26 PHYTOPROTECTION 82 : 49-55 A survey of plant-parasitic and entomopathogenic nematodes associated with vineyards was undertaken in the Estrie and Montérégie regions, the two major grapevine-producing areas in Quebec. Soil samples from 13 sampled vineyards were analyzed for the occurrence of plant-parasitic and entomopathogenic nematodes. Six genera of plant-parasitic nematodes were observed. The most commonly encountered plant-parasitic nematode genera were Pratylenchus and Paratylenchus, both occurring in 85% of sampled vineyards. No Xiphinema sp. were observed in surveyed vineyards. Entomopathogenic nematodes were recovered from 85% of the samples. Heterorhabditid and steinernematid nematodes were isolated from one and 11 vineyards respectively. Steinernematid isolates were identified as Steinernema carpocapsae. [Inventaire des nématodes phytoparasites et entomopathogènes dans des vignobles du Québec] Un inventaire des nématodes phytoparasites et entomopathogènes présents dans des vignobles du Québec a été réalisé dans les régions de l'Estrie et de la Montérégie, les deux principales régions productrices de vignes. Des échantillons de sol provenant de 13 vignobles ont été analysés pour la présence de nématodes phytoparasites et entomopathogènes. Six genres de nématodes phytoparasites ont été observés. Les genres les plus fréquemment retrouvés étaient Pratylenchus et Paratylenchus, lesquels ont été observés dans 85 % des échantillons de sol. Aucun spécimen du genre Xiphinema n'a été retrouvé dans les vignobles. La présence de nématodes entomopathogènes fut notée dans 85 % des vignobles échantillonnés. Des nématodes entomopathogènes de la famille des Steinernematidae ont été observés dans 11 vignobles et des Heterorhabditidae dans un seul vignoble. Tous les isolats de Steinermatidae ont été identifiés comme étant de l'espèce Steinernema carpocapsae.Phytoprotection -Quebec- 01/2001; · 0.25 Impact Factor
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ABSTRACT: Two different molecular tools for the diagnosis of the cereal and legume root-lesion nematode Pratylenchus thornei were developed. A randomly amplified DNA (RAPD) fragment specific to P. thornei was identified. After sequencing the fragment, longer primers were designed that complement the terminal sequences of the RAPD fragment, and this pair of specific primers was used to amplify the sequence-characterized amplified region (SCAR). Using the developed pair of SCAR primers, the SCAR fragment specific to P. thornei was easily amplified with DNA extracts obtained from different life stages of the nematode. The described SCARPCR- based assay has the potential to be optimized for routine practical diagnostic tests. In addition, the use of a species-specific satellite DNA sequence to distinguish P. thornei from other Pratylenchus spp. is discussed. This research was supported by grant AGF98-0878 from Comisión Interministerial de Ciencia y Tecnología (CICYT) of Spain. Peer reviewedEuropean Journal of Plant Pathology 02/2007; 118:115-125. · 1.71 Impact Factor
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ABSTRACT: Three satellite DNAs previously isolated from the entomopathogenic nematodes Steinernema carpocapsae, Heterorhabditis bacteriophora and Heterorhabditis indicus give hybridization signals only with the S. carpocapsae, H. bacteriophora and H. indicus populations tested, indicating that these satellite sequences are species-specific. Because of their reiteration and their variabilities, we have shown that these sequences are able to discriminate at the interspecific level between the Steinernema and Heterorhabditis species, but also at the intraspecific level between S. carpocapsae strains. Furthermore, in simple squashed nematode experiments, we are able to unambiguously identify S. carpocapsae, H. bacteriophora and H. indicus populations. This last procedure is effective even on a single infective juvenile, with the main advantage that it avoids time-consuming DNA extractions.Parasitology 12/1996; 113 ( Pt 5):483-9. · 2.35 Impact Factor