Analysis of Potato virus Y Coat Protein Epitopes Recognized by Three Commercial Monoclonal Antibodies

Abstract

Background Potato virus Y (PVY, genus Potyvirus) causes substantial economic losses in solanaceous plants. Routine screening for PVY is an essential part of seed potato certification, and serological assays are often used. The commercial, commonly used monoclonal antibodies, MAb1128, MAb1129, and MAb1130, recognize the viral coat protein (CP) of PVY and distinguish PVYN strains from PVYO and PVYC strains, or detect all PVY strains, respectively. However, the minimal epitopes recognized by these antibodies have not been identified.Methodology/Principal FindingsSPOT peptide array was used to map the epitopes in CP recognized by MAb1128, MAb1129, and MAb1130. Then alanine replacement as well as N- and C-terminal deletion analysis of the identified peptide epitopes was done to determine critical amino acids for antibody recognition and the respective minimal epitopes. The epitopes of all antibodies were located within the 30 N-terminal-most residues. The minimal epitope of MAb1128 was 25NLNKEK30. Replacement of 25N or 27N with alanine weakened the recognition by MAb1128, and replacement of 26L, 29E, or 30K nearly precluded recognition. The minimal epitope for MAb1129 was 16RPEQGSIQSNP26 and the most critical residues for recognition were 22I and 23Q. The epitope of MAb1130 was defined by residues 5IDAGGS10. Mutation of residue 6D abrogated and mutation of 9G strongly reduced recognition of the peptide by MAb1130. Amino acid sequence alignment demonstrated that these epitopes are relatively conserved among PVY strains. Finally, recombinant CPs were produced to demonstrate that mutations in the variable positions of the epitope regions can affect detection with the MAbs.Conclusions/SignificanceThe epitope data acquired can be compared with data on PVY CP-encoding sequences produced by laboratories worldwide and utilized to monitor how widely the new variants of PVY can be detected with current seed potato certification schemes or during the inspection of imported seed potatoes as conducted with these MAbs.

Prediction of antigenic epitopes for coat protein of Potato virus Y, Egypt

“…The titres of antisera were 1:512 and 1:128 against the virus particles and epitope of the PVY isolate, respectively. These results were in accordance with those of many investigators (Karasev et al, 2010;Nerway and Kassim, 2014;Tian et al, 2014).…”

Graphical genotyping as a method to map Ny (o,n)sto and Gpa5 using a reference panel of tetraploid potato cultivars

“…FESTIEN was characterized for the type of PVY resistance using two well-defined PVY strains representing the PVY strain group O (isolate PVY O -UK; GenBank accession no. JX424837) (Tian and Valkonen 2013 ) and PVY strain group N (isolate PVY N -NTN-Nevski; JX432967) (Tian et al 2014 ). Potato virus A (isolate PVA-U; AJ131402) (Rajamäki et al 1998 ) was also included in the experiments.…”

Detection and molecular characterization of Slovak tomato isolates belonging to two recombinant strains of potato virus Y

“…Moreover, besides mutations, recombination is another evolutionary process shaping the PVY genetic structure and possibly increasing its adaptability and emergence (Karasev et al, 2011). Such complex variability may complicate the correct identification of isolates especially using serological tests (Gugerli and Fries, 1983;Tian et al, 2014).…”