Centro de Investigaciones Biológicas del Noroeste, P.O. Box 128, La Paz, Baja California Sur 23000, México
Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, U. Irapuato, P.O. Box 629, Irapuato, Gto 36500, México
In the state of Baja California Sur, tomatoes (Lycopersicon esculentum Mill.) are cultivated on approximately 1,000 ha. Occurrence of viral diseases is currently causing low yields and severe losses. Virus-like symptoms (severe leaf curling, stunting, reduced leaf size, and mosaic patterns) were observed on 99% of tomato plants in 2002 in La Paz, Baja California Sur. Whiteflies (Bemisia tabaci Gennadius) were present in affected fields and appeared to be associated with the disease. The virus was experimentally transmitted from infected plants to tomato and peppers seedlings by whiteflies and as infectious DNA (replicative form) by mechanical and biolistic inoculation. Symptoms similar to those found in the field were observed in experimental transmission assays. DNA from inoculated plants was extracted and analyzed by DNA hybridization and polymerase chain reaction (PCR) using degenerate (1) and specific (2) primers. The PCR products (1.1 kb) obtained from the common region (GenBank Accession No. AY368336) suggested the presence of a bipartite geminivirus. The nucleotide sequence of the PCR products showed a 98% identity to Pepper golden mosaic virus-Tamaulipas strain (PepGMV-Tam) in the intergenic region (IR). Similar identities (97%) were obtained by using the predicted amino acid sequences of the amino termini of the coat proteins. Identities in the replication proteins (92%) and IR iterative sequence analyses show that the PepGMV-La Paz isolate is a closely related strain of PepGMV-Tam. To our knowledge, this is the first report of PepGMV affecting tomato crops in Baja California Sur, Mexico.
References: (1) M. R. Rojas et al. Plant Dis. 77:340. 1993. (2) I. Torres-Pacheco et al. Phytopathology 86:1186, 1996.