DETECTION AND DISTRIBUTION OF GEMINIVIRUSES IN MEXICO AND THE SOUTHERN UNITED-STATES

Plant samples from important horticultural areas in Mexico and the sou thern United States were collected during several seasons and analyzed for the presence of geminiviruses by a combination of agarose gel ele ctrophoresis, molecular hybridization, and polymerase chain reaction a mplification techniques. A general detection strategy confirmed the pr esence of geminiviruses in all horticultural areas of Mexico in pepper . tomato, tomatillo (Physalis ixocarpa), cucurbits, and tobacco. Speci fic detection procedures showed that pepper huasteco virus is widely d istributed in Mexico; it was found in pepper and tomato samples in bot h coastal areas, as well as in central Mexico. It was also found in pe pper samples from the Rio Grande Valley in southern Texas. Pepper jala peno virus (PJV) and chino del tomate virus (CdTV) showed a more restr icted distribution, although, in all cases, the viruses appeared to be come more widely distributed over time. Partial DNA sequences of PJV a nd CdTV were also obtained. Comparative sequence analysis showed that PJV and the previously described Texas pepper geminivirus are probably strains of the same virus. The name pepper jalapeno virus is, thus, w ithdrawn to avoid further confusion. Similarly, CdTV showed a very hig h level of sequence identity with the recently described tomato leaf c rumple virus (TLCrV), also suggesting that they both are strains of th e same virus.