Universidad de Chile, Facultad de Ciencias Agrono ´micas, Departamento de Sanidad Vegetal, Santiago, Chile Grapevine Viruses in the Atacama Region of Chile Nicola icola Fiore iore,Alan lan Zamorano amorano,Lucia ucia Rivera ivera,Flor lor Gonzalez onza ´ lez,Erwin rwin Aballay ballay,Jaime aime Montealegre ontealegre and Ana na Marıa arı ´a Pino ino AuthorsÕ address: Facultad de Ciencias Agrono´micas, Departamento de Sanidad Vegetal, Universidad de Chile, Avenida Santa Rosa 11315, La Pintana, Santiago, Chile (correspondence to N. Fiore. E-mail: nfiore@uchile.cl) Received March 14, 2011; accepted July 5, 2011 Keywords: detection, grapevine viruses, reverse transcription-polymerase chain reaction, sequence, table grape Abstract Vineyards in the Atacama region in Chile were sur- veyed from 2007 to 2009 for the presence of viruses. This region is an important area of table grape pro- duction, supplying international markets with its fruits in the off season of the Northern Hemisphere. Reverse transcription-polymerase chain reaction (RT-PCR) assay was used to detect the most economically impor- tant grapevine viruses in 1000 samples, including symptomatic and asymptomatic plants. The rate of positive samples was 8.8% for Grapevine leafroll-asso- ciated virus 1 (GLRaV-1), 46.8% for Grapevine leaf- roll-associated virus 2 (GLRaV-2), 9.1% for Grapevine leafroll-associated virus 3 (GLRaV-3), 12.3% for Grapevine virus A (GVA), 30.7% for Grapevine fleck virus (GFkV) and 9.6% for Grapevine fanleaf virus (GFLV). Overall virus infection was 68.7%. DNA sequencing confirmed the identification of viruses in selected samples, and comparative analysis indicated that Chilean isolates have moderate-to-high molecular identities with corresponding virus reference strains selected from GenBank. The high level of viral infec- tion observed indicates that viruses are involved in decreasing table grape production in the region. This is the first extensive virus survey performed in the Ata- cama region, is also the first study of genetic compari- son of grapevine viruses developed in South America with a wide spectrum of viruses and isolates and pro- vides an assessment of grapevine viruses on table grape. Introduction Virus diseases are very important among the factors that limit grape production in the world. In symptom- atic plants infected by Grapevine leafroll-associated virus 1, 2 (GLRaV-1, -2) and Grapevine virus A (GVA), an average reduction in production of 23% has been observed, with a decrease of 5% in sugar content (Digiaro et al. 1997). Specifically, for Grape- vine fanleaf virus (GFLV), the production loss varies between 5% and 10%, even reaching 90% or more; for the GLRaVs, the average is 10% but may be up to 60 or 70%; for the viruses involved in the rugose wood complex, the decrease oscillates between 20% and 30% (Auger et al. 1992; Walter and Martelli 1997; Martelli 1999; Clingeleffer and Krake 2002; Gugerli 2003). It is difficult to estimate the level of damage produced by Grapevine fleck virus (GFkV), due to the latency of the infection, even though it is quite fre- quent in all areas where grapes are cultivated. How- ever, it has been shown that it decreases the percentage of successful grafts, limits root production and reduces plant vigour (Credi and Babini 1996). In asymptomatic plants, a productivity decrease of 5% is observed annually (Golino 1993). Chile currently ranks second worldwide in table grape production, with approximately 53 426 ha of plantations, of which approximately 10 000 ha are in the Atacama region (7500 and 2500 ha in the valleys of Copiapo´ and Huasco, respectively). The main vari- eties in order of importance are Thompson Seedless, Flame Seedless, Red Globe and Superior. The region is important from the standpoint of the table grape exporter due to its price advantage (the highest in the country) and because it provides the international market with its products in the off season of the Northern Hemisphere. During the last decade, the cultivated area increased by approximately 38% in the region. However, in recent years, production lev- els have not been proportional to the increase in cul- tivated area, with yields below the average elsewhere in the country (SAG, 2003; INE 2009, 2011), the presence of plants lacking strength and with low- quality fruit. This event can be partially explained by the deleterious action of some abiotic factors, but mainly by the action of biotic factors such nema- todes, insects and fungi that affect the roots (Gon- za´lez 1984; Auger et al. 2007). A preliminary report of the detection of GFLV, GLRaV-1, GLRaV-2, GLRaV-3, GFkV and GVA in 19 of 40 samples J Phytopathol 159:743–750 (2011) doi: 10.1111/j.1439-0434.2011.01834.x Ó 2011 Blackwell Verlag GmbH