scholarly journals Genotyping Common Bean for the Potyvirus Resistance Alleles I and bc-12 with a Multiplex Real-Time Polymerase Chain Reaction Assay

2005 ◽  
Vol 95 (5) ◽  
pp. 499-505 ◽  
Author(s):  
George J. Vandemark ◽  
Phillip N. Miklas

A multiplex real-time polymerase chain reaction (PCR) assay was developed to simultaneously genotype plants for the I and bc-12 alleles, which condition resistance in beans to Bean common mosaic virus and Bean common mosaic necrosis virus. A segregating F2 population was derived from the cross between pinto bean breeding line P94207-189A (bc-1 bc-1 I I) and Olathe (bc-12 bc-12 i i). Real-time PCR assays were developed that were specific for each allele, and a multiplex PCR reaction could unambiguously assign F2 plants to one of nine genotypes. Remnant F1 plants were used as a comparative reference sample. PCR results among this sample fit a normal distribution for both real-time PCR assays, and 99% probability distributions were determined for heterozygotes. F2 plants were genotyped based on results relative to the probability distributions for heterozygotes. F2 plants also were genotyped for the I and bc-12 alleles by performing F3 family progeny tests for virus resistance. Agreement between the two methods was 100% (198/198) for the bc-12 allele, and 92.4% (183/198) for the I allele. Erroneous genotyping was due to recombination between the amplicon and the I allele. Realtime PCR assays provide a robust method for genotyping seedlings and, in some cases, may eliminate the need for progeny testing.

Pharmacology ◽  
2018 ◽  
Vol 102 (1-2) ◽  
pp. 88-90
Author(s):  
Dietmar Enko ◽  
Sophia Harringer ◽  
Christian Oberkanins ◽  
Helene Pühringer ◽  
Gabriele Halwachs-Baumann ◽  
...  

Statin-induced myopathy is reported to be significantly associated with the SCLO1B1 c.521T>C polymorphism. To date, SLCO1B1 c.521T>C epidemiologic data for the Austrian population is still lacking. Therefore, this study aimed at assessing the genotype and allele frequencies of the SLCO1B1 c.521T>C variant in Austria and evaluating the clinical performance of 2 commercial real-time polymerase chain reaction (PCR) assays. Genomic DNA isolated from 181 healthy individuals was analyzed for the SLCO1B1 c.521T>C polymorphism in a comparative manner using the SLCO1B1 c.521T>C RealFastTM Assay and the BioPro SLCO1B1 Genotyping real-time PCR Kit. A total of 10 (5.5%) and 44 (24.3%) out of 181 individuals were SLCO1B1 c.521T>C C/C-homo- and ­C/T-heterozygotes, the genotypes indicative of high and increased risk of statin-induced myopathy, respectively. The SLCO1B1 c.521C allele frequency rate was 17.7%. In conclusion, the genetic predisposition of elevated statin-induced myopathy risk in the Austrian population is frequent. Both real-time PCR assays under investigation here are reliable and robust SLCO1B1 c.521T>C genotyping tools in clinical routine.


Plant Disease ◽  
2007 ◽  
Vol 91 (4) ◽  
pp. 430-434 ◽  
Author(s):  
M. P. Grisham ◽  
Y.-B. Pan ◽  
E. P. Richard

A real-time, polymerase chain reaction (PCR) assay was developed for detecting Leifsonia xyli subsp. xyli in sugarcane leaf tissue. Real-time PCR assays were conducted on the youngest, fully expanded leaf of three cultivars collected bi-weekly from field nurseries between 11 April and 19 July 2005. L. xyli subsp. xyli infection was detected in leaves collected at all sampling dates, including those from 1-month-old plants on 11 April. Assays conducted on older, more rapidly growing plants (28 July and 21 October 2005) indicated that leaf position affects assay efficiency. Conventional PCR was less efficient than real-time PCR for detecting L. xyli subsp. xyli in leaf tissue. Real-time PCR was used to rank cultivars for susceptibility to L. xyli subsp. xyli infection based on the relative titer of L. xyli subsp. xyli in leaves of inoculated, 3- and 4-month-old greenhouse-grown plants. The ranking of cultivars by real-time PCR was in close agreement with the ranking determined by tissue-blot enzyme immunoassay performed on tissue from 7- to 9-month-old stalks.


Author(s):  
Ika Yasma Yanti ◽  
Dalima Ari Wahono Astrawinata

Toxigenic Clostridium difficile infection, causing a Pseudo Membrane Colitis (PMC) and Clostridium Difficile Associated Diarrhea(CDAD) has increased sharply. The largest risk factor is the use of antibiotics. The purpose of this study was to know how to determinethe prevalence and characteristics of subjects with Toxigenic Clostridium difficile and to assess the ability of the toxin rapid test comparedto real-time PCR. Ninety adult subjects with antibiotic therapy more than two (2) weeks were enrolled in this study. The results of toxinrapid test and real-time PCR were presented in a 2x2 table, statistical test used was Chi square. The prevalence of Toxigenic Clostridiumdifficile based on the toxin rapid test and by real-time PCR was 27.3% and 37.5%, respectively. There were significant differences betweenstool consistency and number of antibiotics used with the detection of Toxigenic Clostridium difficile. There was a relationship betweenthe duration of antibiotic therapy with the detection of Toxigenic Clostridium difficile using real-time PCR (p=0.010, RR=2.116). Thesensitivity, specificity, PPV, NPV, PLR and NLR rapid test against real-time PCR were 69.7%; 98.2%; 95.8%; 84.4%; 39.2 and 0.31,respectively. This study concluded that the prevalence of Clostridium difficile in RSCM was higher compared to that in Malaysia, Thailandand India; the subjects with antibiotic therapy for more than four (4) weeks had a double risk to have Toxigenic Clostridium difficilethan subjects with antibiotic therapy for less than that time (4 weeks). Thus, in this study, toxin rapid test could be used as a tool todetect Toxigenic Clostridium difficile.


2010 ◽  
Vol 134 (3) ◽  
pp. 444-448 ◽  
Author(s):  
Zhengming Gu ◽  
Jianmin Pan ◽  
Matthew J. Bankowski ◽  
Randall T. Hayden

Abstract Context.—BK virus infections among immunocompromised patients are associated with disease of the kidney or urinary bladder. High viral loads, determined by quantitative polymerase chain reaction (PCR), have been correlated with clinical disease. Objective.—To develop and evaluate a novel method for real-time PCR detection and quantification of BK virus using labeled primers. Design.—Patient specimens (n = 54) included 17 plasma, 12 whole blood, and 25 urine samples. DNA was extracted using the MagNA Pure LC Total Nucleic Acid Isolation Kit (Roche Applied Science, Indianapolis, Indiana); sample eluate was PCR-amplified using the labeled primer PCR method. Results were compared with those of a user-developed quantitative real-time PCR method (fluorescence resonance energy transfer probe hybridization). Results.—Labeled primer PCR detected less than 10 copies per reaction and showed quantitative linearity from 101 to 107 copies per reaction. Analytical specificity of labeled primer PCR was 100%. With clinical samples, labeled primer PCR demonstrated a trend toward improved sensitivity compared with the reference method. Quantitative assay comparison showed an R2 value of 0.96 between the 2 assays. Conclusions.—Real-time PCR using labeled primers is highly sensitive and specific for the quantitative detection of BK virus from a variety of clinical specimens. These data demonstrate the applicability of labeled primer PCR for quantitative viral detection and offer a simplified method that removes the need for separate oligonucleotide probes.


2008 ◽  
Vol 98 (5) ◽  
pp. 592-599 ◽  
Author(s):  
Satyanarayana Tatineni ◽  
Uma Shankar Sagaram ◽  
Siddarame Gowda ◽  
Cecile J. Robertson ◽  
William O. Dawson ◽  
...  

Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide, and is caused by a phloem-limited fastidious prokaryotic α-proteobacterium that is yet to be cultured. In this study, a combination of traditional polymerase chain reaction (PCR) and real-time PCR targeting the putative DNA polymerase and 16S rDNA sequence of ‘Candidatus Liberibacter asiaticus,’ respectively, were used to examine the distribution and movement of the HLB pathogen in the infected citrus tree. We found that ‘Ca. Liberibacter asiaticus’ was distributed in bark tissue, leaf midrib, roots, and different floral and fruit parts, but not in endosperm and embryo, of infected citrus trees. Quantification analysis of the HLB bacterium indicated that it was distributed unevenly in planta and ranged from 14 to 137,031 cells/μg of total DNA in different tissues. A relatively high concentration of ‘Ca. Liberibacter asiaticus’ was observed in fruit peduncles. Our data from greenhouse-infected plants also indicated that ‘Ca. Liberibacter asiaticus’ was transmitted systemically from infection site to different parts of the plant. Understanding the distribution and movement of the HLB bacterium inside an individual citrus tree is critical for discerning its virulence mechanism and to develop management strategies for HLB.


2002 ◽  
Vol 92 (7) ◽  
pp. 721-728 ◽  
Author(s):  
N. W. Schaad ◽  
D. Opgenorth ◽  
P. Gaush

Molecular-based techniques, such as polymerase chain reaction (PCR), can reduce the time needed for diagnosis of plant diseases when compared with classical isolation and pathogenicity tests. However, molecular techniques still require 2 to 3 days to complete. To the best of our knowledge, we describe for the first time a real-time PCR technique using a portable Smart Cycler for one-hour on-site diagnosis of an asymptomatic plant disease. Pierce's disease (PD) of grape, caused by the fastidious bacterium Xylella fastidiosa, causes serious losses in grapes in California and the southeastern United States. The disease has been difficult to diagnose because typical leaf scorching symptoms do not appear until late (June and after) in the season and the organism is very difficult to isolate early in the season. Sap and samples of macerated chips of secondary xylem from trunks of vines were used in a direct real-time PCR without extraction of DNA. Using two different sets of primers and probe, we diagnosed PD in 7 of 27 vines (26%) from four of six vineyards sampled 10 to 12 days after bud break in Kern, Tulare, and Napa counties of California. The diagnosis was confirmed by isolation of Xylella fastidiosa from two of the original PCR positive samples and later from symptomatic leaf petioles of four out of four vines from one vineyard that were originally PCR positive.


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