Mìkrobìologìâ ì Bìotehnologìâ (Mar 2013)
DETECTION OF PLUM POX VIRUS ISOLATES IN THE ORCHARDS OF THE EASTERN STE PPE OF U KRAINE
Abstract
Plum pox virus (PPV), the causal agent of Sharka disease, produces severe damage and significant economic losses to stone fruit production. The propagation and distribution of virus free materials into healthy growing areas is one of the main ways to reduce the spread of this virus. Given the aggressiveness of PPV, it is imperative that all infected by this virus plants must be excluded from planting materials. ELIS A method now is one of the most popular and used techniques for PPV detection. Whereas the usage of polyclonal antibodies, which recognize multiple epitopes on any one antigen, is controversial due to problems with specificity and sensitivity because serum contains a mixture of antibodies of different affinity. To ensure the effectiveness of annual screening surveys of rootstocks and varieties nurseries to detect viral pathogens on guaranteeing healthy status of plant material, the minimalizaton of false-negative test results is important. The diagnostic characteristics of two commercially available serological diagnostic tests for the detection of Ukrainian isolates of plum pox virus in plant material of six stone fruit crops selected in the orchards of the Eastern Steppe were evaluated. The standardized methodology was used for the calculation of the parameters of the operational capacity of DAS-ELIS A. The analyses of diagnostic data were performed with 2x2 contingency tables. For assessing the validity of two ELIS A test systems for the detection of local PPV isolates, some diagnostic parameters were calculated: sensitivity and specificity, positive and negative predictive values, positive and negative likelihood ratios. It is shown that the Agdia test system is more specific and more reliably identifies the plant material PPV affected, allowing for a more comprehensive eradication of the virusinfected material. The Agdia test is therefore more useful for the screening of nursery orchards to guarantee the future propagation of PPV-free plant material. Incongruent diagnoses obtained by different diagnostic systems in all stone fruit plant material may evidence that PPV prevalence in the local stone fruit crops orchards being significantly underestimated, may result in the unintended and harmful propagation of the disease.
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