02089naa a2200313 a 450000100080000000500110000800800410001910000190006024500840007926000090016352012650017265000160143765000120145365000110146565000110147665300260148765300160151365300110152970000260154070000180156670000190158470000210160370000210162470000160164570000190166170000140168070000190169477300620171311559622018-05-16       2003    bl uuuu     u00u1 u    #d1 aRIBEIRO, S. G.  aDistribution and genetic diversity of tomato-infecting begomoviruses in Brazil.  c2003  aTomato-infecting begomoviruses have been reported throughout Brazil since the introduction of the B biotype of Bemisia tabaci. Here, we report a large scale survey on the distribution and genetic diversity of tomato-infecting begomoviruses. Tomato samples withtypical begomovirus symptoms were collected in seven different states, comprising the major tomato growing areas of the country. Viruses were detected by polymerase chain reaction (PCR) using universal primers for the genus Begomovirus. PCR-amplified fragments were cloned and sequenced. Based on sequence comparisons and phylogenetic analyses, at least seven previously undescribed species of begomoviruses were found. Four of the new viruses were found exclusively in the Southeastern states, two exclusively in the Northeastern states, and one was found in both regions. Sequence comparisons reveal strong evidence of recombination among the Brazilian begomoviruses.Together, the results indicate the existence of a high degree of pre-existing genetic diversity among tomato-infecting begomoviruses in Brazil and suggest that these viruses have emerged after being transferred from natural hosts to tomatoes, due to he introduction into Brazil of a novel polyfagous biotype of the whitefly vector.  aBegomovirus  aDoença  aTomate  aVírus  aDiversidade genética  aGeminivirus  aTomato1 aAMBROZEVÍCIUS, L. P.1 aÁVILA, A. C.1 aBEZERRA, I. C.1 aCALEGARIO, R. F.1 aFERNANDES, J. J.1 aLIMA, M. F.1 aMLLO, R. N. de1 aROCHA, H.1 aZERBINI, F. M.  tArchives of Virology, New Yorkgv. 148, p. 281-295, 2003.