Since 1997, epidemics of a tomato yellowing disease have occurred in the Málaga and Almería provinces of southern Spain. These epidemics have been associated with infections of Tomato chlorosis virus (ToCV) (genus Crinivirus, family Closteroviridae) (2). During the past few years, an increasing incidence of the disease was observed and it spread to new areas including eastern Spain and the Balearic and Canary Islands (G. Lozano, E. Moriones, and J. Navas-Castillo, unpublished results and ). In 1999, plants of sweet pepper (Capsicum annuum L.) exhibiting symptoms of interveinal yellowing, mild upward leaf curling, and stunting were observed in greenhouses of Almería that were heavily infested with the whitefly, Bemisia tabaci. Symptomatic plants were tested for the presence of the begomovirus, Tomato yellow leaf curl virus, a virus previously reported in sweet pepper (3) by molecular hybridization or polymerase chain reaction (PCR). Some of these plants tested positive. Total RNA extracts from the symptomatic plants were also analyzed for the presence of tomato criniviruses using reverse transcription (RT)-PCR with primers MA59 and MA60 for the HSP70h gene (2). A PCR DNA product of the expected size (587 bp) was obtained from several samples. The cloning and sequencing of the PCR product obtained from one of these samples confirmed the presence of ToCV, with a sequence 100% identical to the equivalent region of the first ToCV isolated from tomato in Málaga (2). Total RNA extracts from plants that tested positive using RT-PCR were also positive with molecular hybridization using a probe for the HSP70h gene of ToCV. To our knowledge, this is the first report of sweet pepper as a natural host of a tomato crinivirus, which may have important epidemiological consequences in regions where both crops are grown. Association between ToCV infection and specific symptoms observed in sweet pepper plants is under study.
References: (1) M. I. Font et al. Bol. San. Veg. Plagas 29:109, 2003. (2) J. Navas-Castillo et al. Plant Dis. 84:835, 2000. (3) J. Reina et al. Plant Dis. 83:1176, 1999.