Occurrence and Molecular Characteristics of Polerovirus BVG Isolates from Poland

Barley virus G (BVG), the species Polerovirus BVG, within the genus Polerovirus in the family Solemoviridae, represents a new threat to cereal crops in Poland. It was first identified in 2022-2023 using high-throughput sequencing in pooled barley samples exhibiting leaf yellowing and stunting symptoms. The presence of BVG was subsequently confirmed by RT-PCR using diagnostic primers described in the literature. A nucleotide BLAST search of the NCBI database revealed sequence identity ranged from 97.8% to 100%. The final results demonstrated mixed infections involving BVG and luteovirus pashordei, formerly barley yellow dwarf virus-PAS (BYDV-PAS). In 2023-2024, BVG was detected in four additional locations across western, southern, south-eastern, and eastern Poland. The virus was found in co-infection with BYDV-PAS in barley and oat, and with mastrevirus hordei, formerly wheat dwarf virus (WDV) in wheat. Due to the mixed nature of BVG infections, a set of total RNA samples previously isolated from BYDV-infected plants was reanalyzed. RT-PCR results confirmed BVG/BYDV-PAS co-infections in samples collected in 2014-2015, 2018-2019, and 2020-2021. These findings indicate that BVG has been present in Poland for at least 10 years. Molecular characteristics were assessed based on the coat protein gene sequence.