Identification and molecular characterization of onion yellow dwarf virus (OYDV) in Allium cepa crops in Poland

Onion yellow dwarf virus is distributed worldwide significantly reducing yield of crops from the Allium genus. The aim of the study was the detection and molecular characterization of newly identified OYDV isolates infecting onions in Poland. The virus was detected by transmission electron microscopy and RT-PCR techniques using two pairs of diagnostic primers: OYDV-NibCPF1/R1 and OYDV-CPF2/R2. The specificity of obtained RT-PCR products was confirmed by Sanger sequencing and received viral coat protein sequence was used for phylogenetic analysis. The phylogenetic analysis was carried out using CP sequences of the new Polish onion isolate obtained in this study and 37 other sequences of OYDV retrieved from GenBank. The analysis revealed that the Polish OYDV isolate is the most similar to the OYDV isolates derived from onions from Argentina and Germany, which may indicate their common origin. Moreover, it was observed that the Polish onion and garlic isolates are very diverse and belong to different phylogroups.