DIFFERENTIAL PROPERTIES OF GRAPEVINE VIRUS B ISOLATES FROM CROATIAN AUTOCHTHONOUS GRAPEVINE CULTIVARS
D. Voncina, S. Šimon, E. Dermic, B. Cvjetkovic, I. Pejic, E. Maletic, J. Karoglan Kontic
A total of 1116 grapevine accessions from 14 different Croatian domestic cultivars were tested for the presence of Grapevine virus B (GVB) by DASI-ELISA. Samples were taken from 51 commercial vineyards in the Dalmatian region. GVB was detected in 35 samples (3.14%) of nine cultivars namely: Dobricic, Mladenka Vlas?ka, Nincus?a, Babic, Plavac mali, Maras?tina, Pos?ip and Vugava. The presence of GVB was further confirmed by molecular and biological assays. RT-PCR conducted on 14 ELISA-positive samples using the primer pair H28/C410 confirmed the serological data. Partial nucleotide sequences of the coat protein and putative RNA binding protein cistrons were generated for the virus isolates from the nine cultivars and compared with each other and other sequenced GVB. Isolates. Analyses showed sequence variation among the Croatian GVB isolates: they shared 81.3-99.5% similarity or 79.8-83.9% similarity with the GVB reference isolate deposited in GenBank. Deduced amino acid sequences of the partial putative RNA-binding protein gene shared between 80.5 and 100% identity within Croatian isolates and 83.2-86.7% with reference isolate. Fourteen GVB-positive samples were selected for further biological characterization by mechanical inoculation onto a range of herbaceous hosts. Symptoms induced on herbaceous hosts varied according to the isolate. In most cases, GVB isolates from domestic Croatian cultivars induced chlorotic spots and/or vein banding in Nicotiana occidentalis and N. cavicola. However, in some cases, symptoms observed in these two hosts included also necrotic local lesions followed by yellowing, deformation and rolling/curling. To the best of our knowledge this is the first report of GVB in Croatia.