First report of grapevine leafroll virus 4 infecting grapevine in Hungary

In 2020 grapevine cultivars infected with different viruses were selected from the grapevine variety collection maintained at Kecskemet for virus elimination. Among them, virome of the in vitro grown, Sarfeher A1 clone were determined using small RNA high-throughput sequencing. Primers were designed on the HTS derived contigs to be able to amplify partial P60, coat protein and P23 encoding part of the viral genome. After Sanger sequencing based on the overlapping regions a 2472nt long part of the viral genome was determined and deposited into the GenBank It high identity with the GLRaV4 showing that this plant was indeed infected with a GLRaV4 strain. In September 2023 leaves were collected from the Sarfeher plant maintained as self-rooted vines in glasshouse. The leaves show no specific viral symptoms. ELISA test of the leaves tested positive using GLRaV4 specific antibody confirming and validating the HTS and RT-PCR results.According to our knowledge this is the first report of GLRaV4, supported by sequence data from Hungary.