scholarly journals Earlyin plantadetection ofXanthomonas axonopodispv.punicaein pomegranate using enhanced loop-mediated isothermal amplification assay

2018 ◽  
Author(s):  
M.K. PrasannaKumar ◽  
P. Buela Parivallal ◽  
C. Manjunath ◽  
H.B. Mahesh ◽  
Karthik S Narayan ◽  
...  

AbstractBacterial blight in pomegranate caused byXanthomonas axonopodispv.punicae(Xap) is an increasing threat for pomegranate cultivation in India. To prevent the economic losses, it is pivotal to detect the infection in latent stages rather than in later stages. We have developed an enhanced method termed as loop-mediated isothermal amplification (LAMP) technique to evaluate for the latent detection of Xap in pomegranate using six set of specific primers. Three DNA intercalating dyes were used, such as Ethidium bromide, hydroxynaphthol blue (HNB) and SYBR Green resulted in visualising the positivity for LAMP assay. The reaction time and temperature were to be 65°C from 30 min onwards, for the dyes and its sensitivity was observed up to 10−7ng in the LAMP assay. For field applicability, LAMP assay detected Xap on 7thday post infection while the PCR amplified Xap after 11thday post infection. Finally, the specificity of LAMP assay was validated to be positive with ten Xap isolates for its accuracy and 29 non-Xap bacterial isolates showed negative results. Moreover, this method could be used as a better alternative to PCR based methods, for early detection of the pathogens.

2020 ◽  
Vol 21 (18) ◽  
pp. 6605
Author(s):  
Maja A. Zaczek-Moczydłowska ◽  
Letitia Mohamed-Smith ◽  
Anna Toldrà ◽  
Chantelle Hooper ◽  
Mònica Campàs ◽  
...  

The Ostreid herpesvirus 1 species affects shellfish, contributing significantly to high economic losses during production. To counteract the threat related to mortality, there is a need for the development of novel point-of-care testing (POCT) that can be implemented in aquaculture production to prevent disease outbreaks. In this study, a simple, rapid and specific colorimetric loop-mediated isothermal amplification (LAMP) assay has been developed for the detection of Ostreid herpesvirus1 (OsHV-1) and its variants infecting Crassostrea gigas (C. gigas). The LAMP assay has been optimized to use hydroxynaphthol blue (HNB) for visual colorimetric distinction of positive and negative templates. The effect of an additional Tte UvrD helicase enzyme used in the reaction was also evaluated with an improved reaction time of 10 min. Additionally, this study provides a robust workflow for optimization of primers for uncultured viruses using designed target plasmid when DNA availability is limited.


Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 909-915 ◽  
Author(s):  
Gavin J. Ash ◽  
Jillian M. Lang ◽  
Lindsay R. Triplett ◽  
Benjamin J. Stodart ◽  
Valérie Verdier ◽  
...  

The vast amount of data available through next-generation sequencing technology is facilitating the design of diagnostic marker systems. This study reports the use of draft genome sequences from the bacterial plant pathogen Pseudomonas fuscovaginae, the cause of sheath brown rot of rice, to describe the genetic diversity within a worldwide collection of strains representing the species. Based on a comparative analysis with the draft sequences, primers for a loop-mediated isothermal amplification (LAMP) assay were developed to identify P. fuscovaginae. The assay reported here reliably differentiated strains of P. fuscovaginae isolated from rice from a range of other bacteria that are commonly isolated from rice and other plants using a primer combination designated Pf8. The LAMP assay identified P. fuscovaginae purified DNA, live or heat-killed cells from pure cultures, and detected the bacterium in extracts or exudates from infected host plant material. The P. fuscovaginae LAMP assay is a suitable diagnostic tool for the glasshouse and laboratory and could be further developed for in-field surveys.


2020 ◽  
Vol 56 (24) ◽  
pp. 3536-3538 ◽  
Author(s):  
Rongxing Zhou ◽  
Yongya Li ◽  
Tianyu Dong ◽  
Yanan Tang ◽  
Feng Li

CRISPR Cas12a enables a sequence-specific plasmonic LAMP assay with dual complementary color readouts.


2014 ◽  
Vol 77 (9) ◽  
pp. 1593-1598 ◽  
Author(s):  
HEE-JIN DONG ◽  
AE-RI CHO ◽  
TAE-WOOK HAHN ◽  
SEONGBEOM CHO

Campylobacter jejuni is a leading cause of bacterial foodborne disease worldwide. The detection of this organism in cattle and their environment is important for the control of C. jejuni transmission and the prevention of campylobacteriosis. Here, we describe the development of a rapid and sensitive method for the detection of C. jejuni in naturally contaminated cattle farm samples, based on real-time loop-mediated isothermal amplification (LAMP) of the hipO gene. The LAMP assay was specific (100%inclusivity and exclusivity for 84 C. jejuni and 41 non–C. jejuni strains, respectively), sensitive (detection limit of 100 fg/μl), and quantifiable (R2 = 0.9133). The sensitivity of the LAMP assay was then evaluated for its application to the naturally contaminated cattle farm samples. C. jejuni strains were isolated from 51 (20.7%) of 246 cattle farm samples, and the presence of the hipO gene was tested using the LAMP assay. Amplification of the hipO gene by LAMP within 30 min (mean =10.8 min) in all C. jejuni isolates (n = 51) demonstrated its rapidity and accuracy. Next, template DNA was prepared from a total of 186 enrichment broth cultures of cattle farm samples either by boiling or using a commercial kit, and the sensitivity of detection of C. jejuni was compared between the LAMP and PCR assays. In DNA samples prepared by boiling, the higher sensitivity of the LAMP assay (84.4%) compared with the PCR assay (35.5%) indicates that it is less susceptible to the existence of inhibitors in sample material. In DNA samples prepared using a commercial kit, both the LAMP and PCR assays showed 100% sensitivity. We anticipate that the use of this rapid, sensitive, and simple LAMP assay, which is the first of its kind for the identification and screening of C. jejuni in cattle farm samples, may play an important role in the prevention of C. jejuni contamination in the food chain, thereby reducing the risk of human campylobacteriosis.


Author(s):  
Jian-min Zhang ◽  
Hai-yan Shen ◽  
Ming Liao ◽  
Tao Ren ◽  
Li-li Guo ◽  
...  

Haemophilus parasuis is the etiological agent of Glässer’s disease, which is characterised by fibrinous polyserositis, meningitis and polyarthritis, causing severe economic losses to the swine industry. In this study, a loop-mediated isothermal amplification (LAMP) test was developed to improve the specificity, facility and speed of diagnosis of H. parasuis isolates. The LAMP assay rapidly amplified the target gene within 50 min incubation at 63 °C in a laboratory water bath. The LAMP amplicon could be visualised directly in the reaction tubes following the addition of SYBR Green I dye. The detection limit of this LAMP method was 10 CFU/mL, which was 10 times more sensitive than the earlier 16S rRNA polymerase chain reaction (PCR) test conducted by Oliveira, Galina and Pijoan (2001), and no cross-reactivity was observed from other non-H. parasuis strains. This LAMP test was evaluated further on 187 clinical specimens from pigs suspected of being infected with H. parasuis. Forty-three were found positive by bacterial isolation of H. parasuis, as well as by the 16S rRNA PCR and LAMP tests. The 43 H. parasuis isolates were classified into 9 serovars and had 37 genetic patterns when analysed by pulsed-field gel electrophoresis (PFGE). This displayed that various H. parasuis serovars and genotypes were widely distributed in South China. Therefore, the speed, specificity and sensitivity of the LAMP test, the lack of a need for expensive equipment, and the visual readout showed great potential for a correct clinical diagnosis of H. parasuis in favour of controlling Glässer’s disease.


Plant Disease ◽  
2016 ◽  
Vol 100 (5) ◽  
pp. 976-983 ◽  
Author(s):  
Yabing Duan ◽  
Ying Yang ◽  
Yong Wang ◽  
Xiayan Pan ◽  
Jian Wu ◽  
...  

The point mutation at codon 200 (TTC→TAC, F200Y) confers moderate resistance to carbendazim in Sclerotinia sclerotiorum. This mutant genotype (F200Y) has been detected mainly by determining the minimum inhibitory concentration (MIC), which requires 3 to 5 days. Here, we developed a loop-mediated isothermal amplification (LAMP) assay for the rapid detection of the F200Y mutant genotype of carbendazim-resistant isolates of S. sclerotiorum. Specific LAMP primers were designed and concentrations of LAMP components were optimized. The optimal reaction conditions were 62 to 63°C for 45 min. The new LAMP assay requires no special equipment and is highly sensitive and specific (the i.e., it generated positive results with F200Y mutant genotype but generated negative results with other carbendazim-resistant mutants and with a variety of carbendazim-resistant mutants of Botrytis cinerea and Fusarium graminearum). Inclusion of the loop backward (LB) primer reduced the reaction time to 15 min. Results were identical with LAMP and MIC determinations. The advantages of the LB-accelerated LAMP assay for detection of the F200Y mutant genotype were demonstrated by assaying sclerotia produced on rape stems that were artificially inoculated in the field. The results indicated that the new LAMP assay represents an improved way to detect the F200Y mutant genotype of carbendazim-resistant isolates of S. sclerotiorum.


2009 ◽  
Vol 60 (8) ◽  
pp. 2167-2172 ◽  
Author(s):  
A. Inomata ◽  
N. Kishida ◽  
T. Momoda ◽  
M. Akiba ◽  
S. Izumiyama ◽  
...  

We describe a novel assay for simple, rapid and high-sensitive detection of Cryptosporidium oocysts in water samples using a reverse transcription-loop-mediated isothermal amplification (RT-LAMP). The assay is based on the detection of 18S rRNA specific for Cryptosporidium oocysts. The detection limit of the developed RT-LAMP assay was as low as 6 × 10−3 oocysts/test tube, which theoretically enables us to detect a Cryptosporidium oocyst and perform duplicated tests even if water samples contain only one oocyst. The developed RT-LAMP assay could more sensitively detect Cryptosporidium oocysts in real water samples than the conventional assay based on microscopic observation.


Plant Disease ◽  
2020 ◽  
Vol 104 (1) ◽  
pp. 198-203
Author(s):  
Bruna Alicia Rafael de Paiva ◽  
Adriane Wendland ◽  
Nara Cristina Teixeira ◽  
Marisa A. S. V. Ferreira

A single loop-mediated isothermal amplification (LAMP) assay was developed for specific detection of both pathogens that cause bacterial blight in common bean, Xanthomonas phaseoli pv. phaseoli (Xpp) and Xanthomonas citri pv. fuscans (Xcf). The objective was to provide a simple, easy-to-use, specific, and sensitive method to investigate the presence of one or both pathogens in plant material and seeds for routine diagnosis. The detection limits for both pathogens were 10 CFU/ml for cell suspensions and 1 fg of DNA, whereas in conventional PCR, the primers detected up to 105 CFU/ml and 1 ng of DNA. Specificity was confirmed by testing DNA from bean leaves, other Xanthomonas species, common fungal and bacterial bean pathogens, and bacteria from the leaf microbiota. The method was tested with bean leaves inoculated with Xpp, and the pathogen could be detected from 4 h up to 15 days postinoculation, even before disease symptoms were visible. When the method was applied to bacterium detection (Xpp or Xcf) in seed lots from infected plants, the bacterium detection rate was 100% (24 of 24). The pathogens were detected in seeds incubated for just 1 h in saline solution (0.85%), reducing the time needed for bacterium detection. The LAMP assay could be useful as a tool in bean bacterial blight management. Rapid and sensitive detection of bacteria in bean seed lots would reduce the risks of planting highly contaminated seeds in environments favorable to blight multiplication.


2011 ◽  
Vol 77 (8) ◽  
pp. 2589-2595 ◽  
Author(s):  
Feifei Han ◽  
Fei Wang ◽  
Beilei Ge

ABSTRACTVibrio vulnificusis a leading cause of seafood-related deaths in the United States. Sequence variations in the virulence-correlated gene (vcg) have been used to distinguish between clinical and environmentalV. vulnificusstrains, with a strong association between clinical ones and the C sequence variant (vcgC). In this study,vcgCwas selected as the target to design a loop-mediated isothermal amplification (LAMP) assay for the rapid, sensitive, specific, and quantitative detection of potentially virulentV. vulnificusstrains in raw oysters. No false-positive or false-negative results were generated among the 125 bacterial strains used to evaluate assay specificity. The detection limit was 5.4 CFU per reaction for a virulentV. vulnificusstrain (ATCC 33815) in pure culture, 100-fold more sensitive than that of PCR. In spiked raw oysters, the assay was capable of detecting 2.5 × 103CFU/g ofV. vulnificusATCC 33815, while showing negative results for a nonvirulentV. vulnificusstrain (515-4c2) spiked at 107CFU/g. After 6 h of enrichment, the LAMP assay could detect 1 CFU/g of the virulentV. vulnificusstrain ATCC 33815. Standard curves generated in pure culture and spiked oysters suggested a good linear relationship between cell numbers of the virulentV. vulnificusstrain and turbidity signals. In conclusion, the LAMP assay developed in this study could quantitatively detect potentially virulentV. vulnificusin raw oysters with high speed, specificity, and sensitivity, which may facilitate better control ofV. vulnificusrisks associated with raw oyster consumption.


2017 ◽  
Vol 61 (4) ◽  
pp. 439-444 ◽  
Author(s):  
Syed Ehtisham-ul-Haque ◽  
Madiha Kiran ◽  
Usman Waheed ◽  
Muhammad Younus

AbstractIntroduction:Mycoplasma gallisepticum is considered the most pathogenic and economically significant avian Mycoplasma spp. for the worldwide poultry industry. The aim of this study was to develop a novel and sensitive real-time loop-mediated isothermal amplification (LAMP) assay based on the amplification of its mgc2 gene sequence for its rapid molecular detection in poultry.Material and Methods: Blood samples from 300 broiler and layer chickens were screened using a rapid serum agglutination (RSA) test. A real-time LAMP reaction was conducted with seropositive swab samples at 60°C for 90 min in an ESEQuant tube scanner using 6-carboxyfluorescein as the reporting dye.Results: The sensitivity of the developed assay was 10 fg/μL of DNA. The assay was found 100% specific, showing no cross-reactivity with other avian Mycoplasma species. The proportion found of the positive samples by the real-time LAMP was 58%. In comparison, the RSA was found to detect 52% of positive cases.Conclusion: The mgc2 real-time LAMP emerged as a more sensitive and accurate method for molecular detection of M. gallisepticum than RSA. Robustness and precision give it applicability as a potential field diagnostic tool for M. gallisepticum control. The study will be beneficial in reducing economic losses that M. gallisepticum inflicts on the poultry industry. This is the first reported development of a real-time LAMP assay based on the amplification of the mgc2 gene sequence using an ESEQuant tube scanner for galline M. gallisepticum detection.


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