First Report of Raspberry bushy dwarf virus on Red Raspberry and Grapevine in Slovenia.

In 2002, severe vein yellowing and partial or complete yellowing of leaves was observed on some shoots of red raspberry (Rubus idaeus) cvs. Golden Bliss and Autumn Bliss. Sap of infected plants of cv. Golden Bliss was inoculated onto Chenopodium quinoa and Nicotiana benthamiana. Faint chlorotic spots were observed on inoculated leaves of C. quinoa approximately 14 days after inoculation but no systemic symptoms appeared. No symptoms were observed on N. benthamiana. Raspberry bushy dwarf virus (RBDV) was detected in the original raspberry plant using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with polyclonal antiserum (Loewe Biochemica, Sauerlach, Germany). Systemic infections of inoculated C. quinoa and N. benthaminana were confirmed using DAS-ELISA. In 2001 and 2002, unusual virus symptoms were observed on grapevine grafts (Vitis vinifera) of cv. Laški Rizling. Symptoms appeared as curved line patterns and yellowing of the leaves. No nepoviruses were found in symptomatic plants, but RBDV was confirmed using DAS-ELISA. RBDV infection was later confirmed in grapevine cv. Štajerska Belina with similar symptoms. RBDV was transmitted mechanically from grapevine to C. quinoa where it was detected by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR). IC-RT-PCR was used to amplify a part of the coat protein gene of the virus from raspberry and grapevine, and the amplification products were sequenced (1). The obtained sequence shared at least 93% nucleotide sequence identity with other known RBDV sequences, which confirmed the serological results. To our knowledge, this is the first report of the natural occurrence of RBDV in grapevine and also of RBDV infection of red raspberry in Slovenia. Reference: (1) H. I. Kokko et al. Biotechniques 20:842, 1996.