scholarly journals Recombinase Polymerase Amplification Assay for Field Detection of Tomato Bacterial Spot Pathogens

2019 ◽  
Vol 109 (4) ◽  
pp. 690-700 ◽  
Author(s):  
A. Strayer-Scherer ◽  
J. B. Jones ◽  
M. L. Paret
Keyword(s):  
Detection Limit ◽  
Pathogenic Bacteria ◽  
Diagnostic Methods ◽  
Recombinase Polymerase Amplification ◽  
Bacterial Spot ◽  
Field Detection ◽  
Field Samples ◽  
Amplification Assay ◽  
Polymerase Chain ◽  
Recombinase Polymerase Amplification Assay

Bacterial spot of tomato is caused by Xanthomonas gardneri, X. euvesicatoria, X. perforans, and X. vesicatoria. Current diagnostic methods for the pathogens are not in-field assays. Recombinase polymerase amplification (RPA) is ideal for in-field detection assays, because it is an isothermal technique that is rapid and more tolerant to inhibitors compared with polymerase chain reaction. Hence, novel RPA probes and primers were designed to amplify regions of the hrcN gene of X. gardneri, X. euvesicatoria, and X. perforans. The X. gardneri RPA is specific to X. gardneri with a detection limit of 106 CFU/ml and detected X. gardneri in lesions from naturally (n = 6) or artificially (n = 18) infected plants. The X. euvesicatoria RPA detects both X. euvesicatoria and X. perforans with a detection limit of 106 CFU/ml and detected both pathogens in plants artificially infected (n = 36) or naturally infected (n = 85) with either X. euvesicatoria or X. perforans. The X. perforans RPA is specific to X. perforans with a detection limit of 107 CFU/ml. Although the X. perforans RPA assay was unable to detect X. perforans from lesions, the X. euvesicatoria RPA was successfully used in field to detect X. perforans from symptomatic field samples (n = 31). The X. perforans RPA was then used to confirm the pathogen in the laboratory. The X. euvesicatoria and X. gardneri RPA is promising for rapid, real-time in-field detection of bacterial spot and one of the first developed among plant pathogenic bacteria.

scholarly journals Development of a Lateral Flow Strip-Based Recombinase Polymerase Amplification Assay for the Detection of Haemonchus contortus in Goat Feces

2021 ◽  
Vol 59 (2) ◽  
pp. 167-171
Author(s):  
Yao-Dong Wu ◽  
Qi-Qi Wang ◽  
Meng Wang ◽  
Hany M. Elsheikha ◽  
Xin Yang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Haemonchus Contortus ◽  
Rapid Detection ◽  
Small Ruminants ◽  
Lateral Flow ◽  
Recombinase Polymerase Amplification ◽  
Lateral Flow Strip ◽  
Specific Sequence ◽  
Amplification Assay ◽  
Recombinase Polymerase Amplification Assay

Haemonchosis remains a significant problem in small ruminants. In this study, the assay of recombinase polymerase amplification (RPA) combined with the lateral flow strip (LFS-RPA) was established for the rapid detection of <i>Haemonchus contortus</i> in goat feces. The assay used primers and a probe targeting a specific sequence in the ITS-2 gene. We compared the performance of the LFS-RPA assay to a PCR assay. The LFS-RPA had a detection limit of 10 fg DNA, which was 10 times less compared to the lowest detection limit obtained by PCR. Out of 24 goat fecal samples, LFS-RPA assay detected <i>H. contortus</i> DNA with 95.8% sensitivity, compared to PCR, 79.1% sensitivity. LFS-RPA assay did not detect DNA from other related helminth species and demonstrated an adequate tolerance to inhibitors present in the goat feces. Taken together, our results suggest that LFS-RPA assay had a high diagnostic accuracy for the rapid detection of <i>H. contortus</i> and merits further evaluation.

Development of a recombinase polymerase amplification assay forVibrio parahaemolyticusdetection with an internal amplification control

2018 ◽  
Vol 64 (4) ◽  
pp. 223-230 ◽  
Author(s):  
Huan-Lan Yang ◽  
Shuang Wei ◽  
Ravi Gooneratne ◽  
Anthony N. Mutukumira ◽  
Xue-Jun Ma ◽  
...  
Keyword(s):  
Bacterial Species ◽  
False Negative ◽  
Recombinase Polymerase Amplification ◽  
Internal Amplification Control ◽  
Target Sequence ◽  
Negative Results ◽  
False Negative Results ◽  
Amplification Assay ◽  
Pcr Method ◽  
Recombinase Polymerase Amplification Assay

A novel RPA–IAC assay using recombinase polymerase and an internal amplification control (IAC) for Vibrio parahaemolyticus detection was developed. Specific primers were designed based on the coding sequence for the toxR gene in V. parahaemolyticus. The recombinase polymerase amplification (RPA) reaction was conducted at a constant low temperature of 37 °C for 20 min. Assay specificity was validated by using 63 Vibrio strains and 10 non-Vibrio bacterial species. In addition, a competitive IAC was employed to avoid false-negative results, which co-amplified simultaneously with the target sequence. The sensitivity of the assay was determined as 3 × 103CFU/mL, which is decidedly more sensitive than the established PCR method. This method was then used to test seafood samples that were collected from local markets. Seven out of 53 different raw seafoods were detected as V. parahaemolyticus-positive, which were consistent with those obtained using traditional culturing method and biochemical assay. This novel RPA–IAC assay provides a rapid, specific, sensitive, and more convenient detection method for V. parahaemolyticus.

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