Studies on geminiviruses in Mexico and Southern United States
In Mexico and some southern states of US, plant samples were collected from important horticultural areas and were tested (electrophoresis, molecular hybridization, PCR) for the presence of geminiviruses. The main crops studied were capsicum, tomato, tomatillo (Physalis ixocarpa), squash and tobacco. A general detection strategy confirmed the presence of geminiviruses in all horticultural areas of Mexico. More specific detection methods showed that pepper huasteco geminivirus which was originally isolated from Tamaulipas (MX) is widely distributed on tomato and capsicum in Mexico (Sinaloa, Tamaulipas, Guanajuato and Quintana Roo). It was also found in capsicum samples from the Rio Grande Valley in southern Texas (US). Pepper jalapeño geminivirus, a partially characterized virus originally isolated from Tamaulipas, and chino del tomate geminivirus showed a more restricted distribution. Chino del tomate geminivirus was found on tomatoes in Chiapas, Sinaloa, Morelos and Tamaulipas. Pepper jalapeño geminivirus was detected in Sinaloa (tomato and capsicum) and Michoacán (capsicum).
In addition, comparative studies on partial DNA sequences were done between: 1) pepper jalapeño geminivirus and Texas pepper geminivirus which was isolated on capsicum from southern Texas; 2) chino del tomate geminivirus and tomato leaf crumple geminivirus, which has recently been observed on tomatoes in Sinaloa (EPPO RS 95/043). Results showed that pepper jalapeño and Texas pepper geminiviruses are closely related and the authors felt that they could be two strains of the same virus. Similarly, chino del tomate and leaf crumple geminiviruses are closely related, and might be considered as two strains of the same virus. To avoid confusion, they suggested that only the names Texas pepper geminivirus and chino del tomate geminivirus should be retained.
Sources
Torres-Pacheco, I.; Garzón-Tiznado, J.A.; Brown, J.K.; Becerra-Flora, A.; Rivera-Bustamante, F.R. (1996) Detection and distribution of geminiviruses in Mexico and the Southern United States.
Phytopathology, 86(11), 1186-1192.