Decision Strategies for Absorbance Readings from an Enzyme-Linked Immunosorbent Assay—A Case Study about Testing Genotypes of Sugar Beet (Beta vulgaris L.) for Resistance against Beet Necrotic Yellow Vein Virus (BNYVV)

Thomas M Lange,Armin O Schmitt,Martin Wutke,Lisa Bertram,Friedrich Kopisch-Obuch,Harald Keunecke

doi:10.3390/agriculture11100956

Thomas M Lange, Armin O Schmitt + Show 4 more

Open Access

https://doi.org/10.3390/agriculture11100956

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Journal: Agriculture	Publication Date: Oct 2, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: University of Göttingen, KWS Saat (Germany)

Abstract

The Beet necrotic yellow vein virus (BNYVV) causes rhizomania in sugar beet (Beta vulgaris L.), which is one of the most destructive diseases in sugar beet worldwide. In breeding projects towards resistance against BNYVV, the enzyme-linked immunosorbent assay (ELISA) is used to determine the virus concentration in plant roots and, thus, the resistance levels of genotypes. Here, we present a simulation study to generate 10,000 small samples from the estimated density functions of ELISA values from susceptible and resistant sugar beet genotypes. We apply receiver operating characteristic (ROC) analysis to these samples to optimise the cutoff values for sample sizes from two to eight and determine the false positive rates (FPR), true positive rates (TPR), and area under the curve (AUC). We present, furthermore, an alternative approach based upon Bayes factors to improve the decision procedure. The Bayesian approach has proven to be superior to the simple cutoff approach. The presented results could help evaluate or improve existing breeding programs and help design future selection procedures based upon ELISA. An R-script for the classification of sample data based upon Bayes factors is provided.

Highlights

Rhizomania was first recorded in 1952 in the North of Italy [1]
An alternative approach based upon Bayes factors to improve the decision procedure
Rhizomania is spread in sugar beet growing areas worldwide and counts as one of the most destructive soil-borne diseases of sugar beet (Beta vulgaris L.) with loss of root yield of up to 90 % and reduced sugar yield by up to 80% [7]

Summary

Introduction

Rhizomania was first recorded in 1952 in the North of Italy [1]. In 1973 the Beet necrotic yellow vein virus (BNYVV), a member of the genus Benyvirus, was identified as the causal agent of rhizomania [2]. BNYVV, which is transmitted by the soil-borne fungus Polymyxa betae Keskin [3,4,5], had already spread across wide parts of Europe and Japan [6]. Rhizomania is spread in sugar beet growing areas worldwide and counts as one of the most destructive soil-borne diseases of sugar beet (Beta vulgaris L.) with loss of root yield of up to 90 % and reduced sugar yield by up to 80% [7]. The enzyme-linked immunosorbent assay (ELISA) counts as the standard tool in microbiology to estimate the concentration of a specific protein in a sample [8]. Double antibody sandwich-ELISA (DAS-ELISA) [7,9,10,11] and triple antibody sandwich-ELISA (TAS-ELISA) [12,13,14] have been adapted as tools to detect BNYVV in a sample either for qualitative detection where only the presence or absence of the organism is analysed [7], semi-quantitative detection where absorbance levels of the ELISA machine are analysed [11] or quantitative detection where virus concentrations are analysed [10,15,16]

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Conclusion