Resumo

QUINONES, Madelaine; FONSECA, D  e  MARTINEZ, Yamila. MOLECULAR CHARACTERIZATION OF FIELD ISOLATES OF TOMATO YELLOW LEAF CURL VIRUS (TYLCV). Rev. Protección Veg. [online]. 2007, vol.22, n.1, pp. 47-56. ISSN 2224-4697.

Begomoviruses are plant emergent viruses. Due to the persistent TYLCV infections in tomato fields, the losses caused by theses viruses in the worldwide agriculture and the high variability reported for most of their members, the objective of this work was to characterize the genetic variability of the natural population of TYLCV in Cuba. Twenty one isolates of TYLCV, collected from several years and regions of the country, were amplified and sequenced using specific primers that amplify the intergenic region (IR) and the 5` end of c1 gene or replication protein (rep). The sequences obtained were analyzed by bioinformatic softwares to determine the phylogenetic relationship with other TYLCV isolates reported in Genkbank, and predict possible secondary structures. Results evidenced the presence of an only one TYLCV population in the country, where all the isolates showed between 97-99% identity of their nucleotide sequences with that TYLCV previously isolated in Cuba. The presence of three different secondary structures with high thermodynamic stability was determined, being the predominant structure similar to that of TYLCV-Egypt and different from that of TYLCV-Isr. These results provide new elements for the characterization of the genetic diversity and control of TYLCV, and could explain the possible causes of the wide dissemination of the virus observed in the Cuban tomato fields.

Palavras-chave : TYLCV; begomoviruses; tomato; genetic variability; PCR; sequencing; secondary structure.

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