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Identification of Tomato yellow leaf curl virus-Is in The Bahamas

In December 1996, symptoms of stunting, curling, and marginal chlorosis of leaves, reduced leaf size, and marked reduction in number of fruits were first seen in tomato (Lycopersicon esculentum) plants on the island of North Andros, The Bahamas. Similar symptoms were observed for the first time during fall 1997 in tomatoes on the island of Eleuthera. Incidences of symptomatic plants were as high as 100% in some fields. Leaves from one symptomatic plant from each island were collected during April 1998. DNA was extracted from the samples and tested by polymerase chain reaction (PCR) amplification for the presence of one or more geminiviruses (2). Three sets of primers were used to amplify the extracts: PAL1c496 and PAL1v1978, which amplify an ≈1,100- or ≈1,300-bp DNA product from the A component of a wide range of bipartite and monopartite begomoviruses, respectively; primers PCRc154 and PBL1v2042, which amplify an ≈600-bp DNA fragment from the B component of a wide range of bipartite geminiviruses; and primers PCRc154 and PTYC1v2180 (5′ACTACCATGGCCGC-GCAGCGGAATAC3′), which preferentially amplify Tomato yellow leaf curl virus (TYLCV-Is) (1,2). DNA products of ≈1,300 and ≈780 bp were amplified with PAR1c496 and PAL1v1978 and PCRc154 and PTYC1v2180, respectively, from one sample from each island. No product was obtained from primers PCRc154 and PBL1v2042. The symptoms and PCR results are consistent for the presence of TYLCV. PCR products generated by primers PAL1c496 and PAL1v1978 from each sample were cloned into a pGEM-T Easy Vector (Promega, Madison, WI), and one clone from each was sequenced with vector primers. The sequences of the two 1,300-nt Bahamian clones were identical. The Bahamian clones shared 98.9% sequence homology with equivalent sequences of a TYLCV-Is clone from Florida, 99.2 and 99.4% homology with two TYLCV-Is clones from the Dominican Republic (GenBank Accession no. AF024715, and a full-length infectious clone submitted to GenBank), 98.7% homology with a clone from Cuba (GenBank Accession no. AJ223505), and 98.0% homology with the type sequence from Israel (GenBank Accession no. X15656). A deletion (28 or 29 nt) in the intergenic region was shared by clones from The Bahamas and Florida but was not present in clones from Cuba (AJ223505), the Dominican Republic (AF024715), Egypt (GenBank Accession no. L12219), Israel (X15656), Jamaica (GenBank Accession no. U84146), Lebanon (GenBank Accession no. AF160875), Mexico (GenBank Accession no. AF168709), and Spain (GenBank Accession no. AJ223505). TYLCV-Is appeared in The Bahamas and Florida at almost the same time (1). Because clones from both locations share an unusual deletion, there may be a common source for both introductions. This is the first report of TYLCV-Is in The Bahamas.

Reference: (1) J. E. Polston et al. Plant Dis. 83:984, 1999. (2) M. R. Rojas et al. Plant Dis. 77:340, 1993.