scholarly journals Specific Detection of the Root-Lesion Nematode Pratylenchus scribneri Using Conventional and Real-Time PCR

Plant Disease ◽  
2017 ◽  
Vol 101 (2) ◽  
pp. 359-365 ◽  
Author(s):  
Danqiong Huang ◽  
Guiping Yan

Pratylenchus scribneri is a plant-parasitic root-lesion nematode causing economic damage to various crops worldwide. Identifying root-lesion nematodes to species using traditional morphological methods is an arduous task requiring extensive training on nematode taxonomy and years of experience. Thus, molecular methods for P. scribneri detection and identification were developed. Conventional and real-time polymerase chain reaction (PCR) assays with new species-specific primers were used in this study, which exclusively amplified DNA of P. scribneri but not DNA from other Pratylenchus spp. or non-Pratylenchus spp. tested. Compared with conventional PCR that was able to detect an equivalent to 1/4 of the DNA of a single nematode, real-time PCR was more sensitive and could amplify an equivalent to 1/128 of the DNA of one nematode. Both conventional and real-time PCR assays successfully identified P. scribneri and distinguished it from P. penetrans and P. neglectus isolated from field samples collected from various locations in North Dakota and Minnesota. The Blast-search based on the sequence information confirmed the reliability of the PCR assays for species identification. This is the first report of P. scribneri identification using a real-time PCR assay. The developed PCR assays are suitable for use in diagnostic laboratories and detection of field infestations with this nematode species.

2021 ◽  
Vol 22 (11) ◽  
pp. 5872
Author(s):  
Intiaz Amin Chowdhury ◽  
Guiping Yan

A rapid and accurate PCR-based method was developed in this study for detecting and identifying a new species of root-lesion nematode (Pratylenchus dakotaensis) recently discovered in a soybean field in North Dakota, USA. Species-specific primers, targeting the internal transcribed spacer region of ribosomal DNA, were designed to be used in both conventional and quantitative real-time PCR assays for identification of P.dakotaensis. The specificity of the primers was evaluated in silico analysis and laboratory PCR experiments. Results showed that only P.dakotaensis DNA was exclusively amplified in conventional and real-time PCR assays but none of the DNA from other control species were amplified. Detection sensitivity analysis revealed that the conventional PCR was able to detect an equivalent to 1/8 of the DNA of a single nematode whereas real-time PCR detected an equivalent to 1/32 of the DNA of a single nematode. According to the generated standard curve the amplification efficiency of the primers in real-time PCR was 94% with a R2 value of 0.95 between quantification cycle number and log number of P.dakotaensis. To validate the assays to distinguish P.dakotaensis from other Pratylenchus spp. commonly detected in North Dakota soybean fields, 20 soil samples collected from seven counties were tested. The PCR assays amplified the DNA of P.dakotaensis and discriminated it from other Pratylenchus spp. present in North Dakota soybean fields. This is the first report of a species-specific and rapid PCR detection method suitable for use in diagnostic and research laboratories for the detection of P.dakotaensis.


2005 ◽  
Vol 3 (9) ◽  
pp. 381-391 ◽  
Author(s):  
Kathryn J. Coyne ◽  
Sara M. Handy ◽  
Elif Demir ◽  
Edward B. Whereat ◽  
David A. Hutchins ◽  
...  

Plant Disease ◽  
2017 ◽  
Vol 101 (6) ◽  
pp. 964-972 ◽  
Author(s):  
Danqiong Huang ◽  
Guiping Yan ◽  
Andrea M. Skantar

Paratrichodorus allius is an important pest on many crops, particularly on potato due to its ability to transmit Tobacco rattle virus causing corky ringspot disease on tubers. Detection and identification of P. allius are important for effective disease management. In this study, a rapid and reliable molecular diagnosis of this nematode targeting internal transcribed spacer ribosomal DNA was established. The specificity of the designed primers was evaluated using 29 nematode species and results showed that a single amplicon was produced from DNA of P. allius only. Detection sensitivity analysis indicated that a 9.6 × 10−4 ng of DNA template could be detected by conventional PCR and 1.92 × 10−4 ng of DNA by real-time PCR. The PCR assays amplified DNA of stubby root nematodes isolated from 18 soil samples in North Dakota and Minnesota, which were confirmed as P. allius by sequencing. Both conventional PCR and real-time PCR assays amplified target nematodes from complex nematode communities, supporting the success of this molecular diagnosis of P. allius. This is the first report of P. allius identification using the real-time PCR method and from nematode communities with other nematodes using conventional PCR. The new PCR assays provide rapid species identification and are suitable for use in diagnostic laboratories and detection of field infestations with P. allius.


2017 ◽  
Author(s):  
Katharina Kopp

AbstractFirst evaluations on field samples, including carnivore feces, animal and human hydatid cyst material from Uganda and Kenya, showed specific amplification of two target regions of the mitochondrial genome ofEchinococcusspecies according to melt and high-resolution melt curve analyses of the developed real-time PCR assays. Consecutive sequencing of PCR products revealed that, apart fromEchinococcus felidis, sequences of two other tapeworm species,Echinococcus granulosussensu stricto andEchinococcus canadensis, which are also endemic in East Africa, were detected by the developed real-time PCR assays.


2008 ◽  
Vol 74 (23) ◽  
pp. 7174-7182 ◽  
Author(s):  
Anna Godhe ◽  
Maria E. Asplund ◽  
Karolina Härnström ◽  
V. Saravanan ◽  
Anuj Tyagi ◽  
...  

ABSTRACT Two real-time PCR assays targeting the small-subunit (SSU) ribosomal DNA (rDNA) were designed to assess the proportional biomass of diatoms and dinoflagellates in marine coastal water. The reverse primer for the diatom assay was designed to be class specific, and the dinoflagellate-specific reverse primer was obtained from the literature. For both targets, we used universal eukaryotic SSU rDNA forward primers. Specificity was confirmed by using a BLAST search and by amplification of cultures of various phytoplankton taxa. Reaction conditions were optimized for each primer set with linearized plasmids from cloned SSU rDNA fragments. The number of SSU rDNA copies per cell was estimated for six species of diatoms and nine species of dinoflagellates; these were significantly correlated to the biovolumes of the cells. Nineteen field samples were collected along the Swedish west coast and subjected to the two real-time PCR assays. The linear regression of the proportion of SSU rDNA copies of dinoflagellate and diatom origin versus the proportion of dinoflagellate and diatom biovolumes or biomass per liter was significant. For diatoms, linear regression of the number of SSU rDNA copies versus biovolume or biomass per liter was significant, but no such significant correlation was detected in the field samples for dinoflagellates. The method described will be useful for estimating the proportion of dinoflagellate versus diatom biovolume or biomass and the absolute diatom biovolume or biomass in various aquatic disciplines.


2019 ◽  
pp. 60-66
Author(s):  
Viet Quynh Tram Ngo ◽  
Thi Ti Na Nguyen ◽  
Hoang Bach Nguyen ◽  
Thi Tuyet Ngoc Tran ◽  
Thi Nam Lien Nguyen ◽  
...  

Introduction: Bacterial meningitis is an acute central nervous infection with high mortality or permanent neurological sequelae if remained undiagnosed. However, traditional diagnostic methods for bacterial meningitis pose challenge in prompt and precise identification of causative agents. Aims: The present study will therefore aim to set up in-house PCR assays for diagnosis of six pathogens causing the disease including H. influenzae type b, S. pneumoniae, N. meningitidis, S. suis serotype 2, E. coli and S. aureus. Methods: inhouse PCR assays for detecting six above-mentioned bacteria were optimized after specific pairs of primers and probes collected from the reliable literature resources and then were performed for cerebrospinal fluid (CSF) samples from patients with suspected meningitis in Hue Hospitals. Results: The set of four PCR assays was developed including a multiplex real-time PCR for S. suis serotype 2, H. influenzae type b and N. meningitides; three monoplex real-time PCRs for E. coli, S. aureus and S. pneumoniae. Application of the in-house PCRs for 116 CSF samples, the results indicated that 48 (39.7%) cases were positive with S. suis serotype 2; one case was positive with H. influenzae type b; 4 cases were positive with E. coli; pneumococcal meningitis were 19 (16.4%) cases, meningitis with S. aureus and N. meningitidis were not observed in any CSF samples in this study. Conclusion: our in-house real-time PCR assays are rapid, sensitive and specific tools for routine diagnosis to detect six mentioned above meningitis etiological agents. Key words: Bacterial meningitis, etiological agents, multiplex real-time PCR


2019 ◽  
Vol 20 (2) ◽  
pp. 6-11
Author(s):  
Aly El-Kenawy ◽  
Mohamed El-Tholoth ◽  
Emad A

In the present study, a total of 16 samples including feather follicle epithelium, ovary, spleen and kidney (4 samples for each organ) were collected from diseased chicken flocks suspected to be infected with Marek’s disease virus (MDV) at Dakahlia Governorate, Egypt during the period from October 2016 to October 2017. Each sample was pooled randomly from three to five birds (90 to 360 days old). The isolation of the suspected virus from the collected samples was carried out via chorioallantoic membranes (CAMs) of 12 days old embryonated chicken eggs (ECEs). Three egg passages were carried out for each sample. Hyperimmune serum was prepared against standard MDV. MDV in both field and egg passaged samples (after 3rd passage) was identified by agar gel precipitation test (AGPT) and indirect fluorescence antibody test (IFAT). Molecular identification of virus was carried out by conventional polymerase chain reaction (PCR) and real- time PCR in four selected samples. The results revealed that 14 samples (87.5%) including 4 (100%) samples from feather follicle epithelium, ovary and kidney and 2 (50%) samples from spleen, showed positive results in virus isolation after 3rd passage. The positive results percentage by AGPT for field samples were 50% (8 out of 16 samples), while after the 3rd passage in ECEs were 37.5% (6 out of 16 samples) and the positive results percentage by IFAT for field samples were 62.5% (10 out of 16 samples), while after the 3rd passage in ECEs were 81.25 % (13 out of 16 samples). Viral nucleic acid was detected in all selected samples by conventional and real- time PCR. The results indicate that feather follicle epithelium is the best organ for MDV detection. IFAT is superior over AGPT in virus detection. Conventional and real - time PCR could be efficiently used for molecular detection of the virus.


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