|A new virus isolated from wild raspberry exhibiting leaf curl symptoms|
A. DIAZ-LARA (1), J. Dittrich (2), K. E. Keller (2), R. R. Martin (3). (1) Oregon State University, Corvallis, OR, U.S.A.; (2) USDA-ARS Horticultural Crops Research Unit, Corvallis, OR, U.S.A.; (3) USDA ARS, Corvallis, OR, U.S.A.
Raspberry leaf curl disease was first reported in the 1920s and reported only in North America. Previous studies suggested an aphid transmitted virus as the causal agent of the disease. During a field survey in the state of Wisconsin a wild black raspberry (<i>Rubus sp.</i>) showing leaf curl and mosaic symptoms was collected and analyzed by means of PCR and ELISA tests, with negative results for all the known viruses affecting <i>Rubus</i> species except for <i>Rubus yellow net virus</i>. DsRNA analysis suggested the presence of a virus with a genome size ~10 Kb. The dsRNA virus was subjected to shotgun cloning, sequencing and analysis using BLAST. The two most closely related viruses identified were two carlaviruses (<i>Elderberry carlavirus C</i> and <i>D</i>), but whose genomes are smaller and are not reported in <i>Rubus sp</i>. Universal <i>Carlavirus</i> primers amplified a 200 bp amplicon confirming the presence of the viruses in the collected and grafted plants. Additionally, a <i>R. idaeus</i> cv. Munger grafted with the wild raspberry developed similar symptoms and the presence of <i>Carlavirus</i> nucleic acids was confirmed with the above mentioned primers. Together these results suggest the existence of a new <i>Carlavirus</i> affecting raspberry, which is graft-transmissible and may be involved in the raspberry leaf curl disease. Currently NGS is being used to further analyze the nucleic acids extracted from the wild black raspberry.