DISTRIBUTION AND DIVERSITY OF GEMINIVIRUSES IN TRINIDAD-AND-TOBAGO

Seven crop and eight weed species from 12 agricultural locations in Tr inidad and Tobago were assayed for the presence of whitefly-transmitte d geminiviruses (WTGs) by using dot blot hybridization and polymerase chain reaction (PCR) amplification of the N-terminal coat protein sequ ence with degenerate primers. The amplified fragments were cloned and analyzed by restriction enzyme digestion to determine fragment length polymorphism among the cloned fragments. Representative clones were th en sequenced and subjected to phylogenetic analysis to determine the s equence similarity to known WTGs. WTGs were found in every location sa mpled and in 10 of the 15 species investigated: Lycopersicon esculentu m (tomato), Capsicum annuum (pepper), Capsicum frutescens (sweet peppe r), Abelmoschus esculentus (okra), Phaseolus vulgaris (beans), Alterna nthera tenella, Desmodium frutescens, Euphorbia heterophylla, Malva al ceifolia, and Sida acuta. The geminiviruses infecting these plants wer e closely related to potato yellow mosaic virus from Venezuela (PYMV-V E) and tomato leaf curl virus from Panama (ToLCV-PA). However, in pepp er, sweet pepper, okra, Alternanthera tenella, Euphorbia heterophylla, Desmodium frutescens, and in one sample of tomato, a PYMV-VE-related virus was found in mixed infections with a virus related to pepper hua steco virus. Full-length infectious DNA-A and DNA-B of a tomato-infect ing geminivirus from Trinidad and Tobago were cloned and sequenced. DN A-A appears to be a recombinant derived from PYMV-VE or ToLCV-PA, and Sida golden mosaic from Honduras. The implications of these findings i n the control of WTGs are discussed.