10 ref. Sum. (En)

In October, 1998, geminivirus-like symptoms were widespread in tomato plantings near Turrialba, Costa Rica. Isolates from several fields were experimentally transmitted to tomato seedlings using whiteflies from a Bemisia tabaci (Genn.) colony maintained at CATIE, which resulted in interveinal chlorosis and leaf curling symptoms indistinguishable from those observed in the field. Total DNA was extracted from leaves of sixteen of these experimentally-inoculated plants and assayed by polymerase chain reaction (PCR) for the presence of begomovirus DNA using the degenerate primers AV324 and AC889 amplify the core region of the coat protein gene (core Cp). PCR yielded the expected size core Cp fragment (576 bp) from 16 of 16 samples. The core Cp fragments of six samples were cloned and sequenced. A comparison of the core Cp sequences with reference begomovirus sequences indicated all Costa Rica isolates were >95 percent identical to Sinaloa tomato leaf curl geminivirus reported in 1994 from Sinaloa, Mexico (STLCV-SINALOA). Virus identity was confirmed by multiple sequence alignments of the viral coat protein gene (Cp) and the common region sequences of A and B components (CR-A and CR-B), respectively, with analogous reference begomovirus sequences. Collectively STLCV-like symptoms in tomato identity between viral Cp sequences, and identical CR iterons indicate that the Costa Rican tomato virus is STLCV, or a closely related strain. This is the first report of a STLCV-like begomovirus in tomato in Costa Rica (STLCVCR).