Occurrence of Tomato yellow leaf curl virus in tomato in Martinique, Lesser Antilles

During April of 2002, symptoms of stunting and chlorotic curled leaves of reduced size, similar to those caused by Tomato yellow leaf curl virus (TYLCV), were observed for the first time in commercial tomato (Solanum lycopersicum) in the northwest region of Martinique. Six months later, many tomato fields had more than 80% of plants expressing these symptoms and yield was drastically reduced. Samples from two symptomatic plants were collected and analyzed by PCR. Primers PC1 (5'-TGACTATGTCGAAGCGACCAGG-3') and PC2 (5'-CGACATTACAGCCTCAGACTGG-3') were used to amplify a 950-bp fragment within the coat protein gene (CP) of TYLCV species (1). Primer pair MP16-MP82 (2) amplified a 550-bp fragment from the conserved nonanucleotide sequence (TAATATTAC) to the 5' end of the CP gene. Products of expected sizes were obtained with both pairs of primers from symptomatic samples but not from uninfected ones. The two overlapping PCR products were cloned into a pGEM-T Easy Vector (Promega, Madison, WI) and sequenced. A BLAST analysis was conducted with begomovirus sequences available in the GenBank database at the NCBI, and DNAMAN software (Lynnon Corporation, Quebec, Canada) was used for further comparisons. The 1275-bp sequence (GenBank Accession No. EF490995) shared 99% nucleotide identity with the partial sequences of TYLCV from Antigua and Barbuda (GenBank Accession No. EF028240), Saint Kitts and Nevis (GenBank Accession No. EF028239), and the two overlapping sequences from Guadeloupe (GenBank Accessions No. AY319645 and AY319646). It was at least 98% identical to TYLCV isolates from Florida (GenBank Accession No AY530931), Dominican Republic (GenBank Accession No. AF024715), and Cuba (GenBank Accession No. AJ223505). These results confirm the introduction of TYLCV into Martinique, possibly from a nearby Caribbean country, and reveal its southward spread in the Lesser Antilles. The nearness of the islands in the Lesser Antilles (20 to 100 km distant) probably permitted the rapid spread of TYLCV through the movement of plant material or wind transport of viruliferous whiteflies from one island to the next. Monitoring the spread of TYLCV in this Caribbean archipelago is important for regional virus management and in forecasting the spread of TYLCV to nearby countries in South America. (Résumé d'auteur