Detection of the Cassava Bacterial Blight Pathogen, Xanthomonas axonopodis pv. manihotis, by Polymerase Chain Reaction

Cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis, is of significant concern wherever cassava is grown. The movement of infected, asymptomatic stems is a major means of pathogen dispersal. A reliable and sensitive diagnostic procedure is necessary for the safe movement of cassava planting material. We used a cloned and sequenced pathogenicity gene of X. axonopodis pv. manihotis to develop a polymerase chain reaction (PCR) test for this pathogen. A set of primers directed the amplification of an 898-bp fragment in all 107 pathogenic strains of X. axonopodis pv. manihotis tested. PCR products were not observed when genomic DNA was tested for 27 strains of other xanthomonads, for saprophytic bacteria, or for five nonpathogenic strains of X. axonopodis pv. manihotis. The primers worked well for pathogen detection in direct PCR assays of X. axonopodis pv. manihotis colonies grown on liquid medium and in PCR assays of extracts from leaf and stem lesions. The minimum number of cells that could be detected from cassava stem and leaf lesions was 3 × 102 to 104 CFU/ml. The PCR assays proved to be relativyel sensitive and could become very useful in detecting the pathogen in cassava planting material.

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Prevalence and polymerase chain reaction detection of Xanthomonas axonopodis pv. manihotis causal agent of cassava bacterial blight disease in Osun state, Southwestern Nigeria

Nigerian Journal of Biotechnology ◽

10.4314/njb.v36i1.21 ◽

2019 ◽

Vol 36 (1) ◽

pp. 159

Author(s):

V.O. Dania ◽

T.D. Ojeyemi

Keyword(s):

Polymerase Chain Reaction ◽

Bacterial Blight ◽

Polymerase Chain Reaction Detection ◽

Chain Reaction ◽

Southwestern Nigeria ◽

Cassava Bacterial Blight ◽

Xanthomonas Axonopodis ◽

Polymerase Chain ◽

Bacterial Blight Disease ◽

Blight Disease

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Detection of Xanthomonas axonopodis pv. manihotis, the causal agent of cassava bacterial blight diseases in cassava (Manihot esculenta) in Ghana by polymerase chain reaction

European Journal of Plant Pathology ◽

10.1007/s10658-017-1297-3 ◽

2017 ◽

Vol 150 (2) ◽

pp. 471-484

Author(s):

Muntala Abdulai ◽

Hüseyin Basım ◽

Esin Basım ◽

Derya Baki ◽

Nurhan Öztürk

Keyword(s):

Polymerase Chain Reaction ◽

Manihot Esculenta ◽

Bacterial Blight ◽

Causal Agent ◽

Chain Reaction ◽

Cassava Bacterial Blight ◽

Xanthomonas Axonopodis ◽

Polymerase Chain

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Evaluation of Sandwich Enzyme-Linked Immunosorbent Assay and Reverse Transcription Polymerase Chain Reaction for the Diagnosis of Foot-and-Mouth Disease

Intervirology ◽

10.1159/000517003 ◽

2021 ◽

pp. 1-6

Author(s):

Salman Khan ◽

Syed Asad Ali Shah ◽

Syed Muhammad Jamal

Keyword(s):

Polymerase Chain Reaction ◽

Viral Genome ◽

Foot And Mouth Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Rt Pcr ◽

Chain Reaction ◽

Kappa Value ◽

Polymerase Chain ◽

Pcr Assays ◽

Level Of Agreement

Background: Foot-and-mouth disease (FMD) is an infectious and highly contagious disease of cloven-hoofed domestic and wild animals, causing heavy economic losses to the livestock industry. Rapid and reliable diagnosis of the disease is essential for the implementation of effective control measures. This study compared sandwich enzyme-linked immunosorbent assay (S-ELISA) and conventional reverse transcription polymerase chain reaction (RT-PCR) for the diagnosis of FMD. Methods: A total of 60 epithelial samples from suspected cases of FMD were tested using both S-ELISA and RT-PCR assays. The level of agreement between the assays was assessed by calculating the Kappa value. Results: S-ELISA detected 38 (63%) samples positive for FMD virus (FMDV). Being predominant, serotype O was detected in 22 (57.9%) of the total samples tested positive, whereas 9 (23.7%) and 7 (18.4%) samples were found positive for serotypes A and Asia-1, respectively. RT-PCR detected viral genome in 51 (85%) of the samples using pan-FMDV primers set, 1F/1R. Thirty-six samples were found positive and 7 negative by both the tests. The level of agreement between the tests was assessed by calculating the Kappa value, which was found to be fair (Kappa value = 0.303 and 95% CI = 0.089; 0.517) and significant (p = 0.009). However, 2 samples, which were found positive on S-ELISA tested negative on RT-PCR. This may be attributed to the presence of nucleotide mismatch(es) in the primer-binding sites that may have resulted in failure of amplification of the viral genome. The serotype-specific RT-PCR assays not only confirmed serotyping results of S-ELISA but were also able to establish serotype in 9 S-ELISA-negative but pan-FMDV RT-PCR-positive samples. Conclusions: The RT-PCR assay contributes significantly to establishing a quick, sensitive, and definitive diagnosis of FMD in resource-constrained countries. Samples giving negative results in S-ELISA should be tested in RT-PCR for the disease detection and virus typing.

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