Polyclonal rabbit antisera were produced to the coat protein of Bean golden mosaic virus Brazil isolate (BGMV), Cabbage leaf curl virus (CabLCV), Tomato yellow leaf curl virus (TYLCV), and Tomato mottle virus (ToMoV), all expressed in Escherichia coli by the pETh expression vector. The expressed coat protein of each virus was purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for use as an immunogen. The antisera to BGMV, CabLCV, TYLCV, and ToMoV reacted in indirect (plate-trapping) enzyme-linked immunosorbent assay (ELISA) with extracts from begomovirus-infected tissue. The antisera to BGMV, CabLCV, TYLCV, and ToMoV also reacted specifically with the test begomovirus antigens in leaf imprint blots and Western blots. The CabLCV and TYLCV antisera were used to detect Bean golden yellow mosaic virus antigens by immunogold labeling of thin sections of infected bean tissues. In tissue blot immunoassays, the TYLCV antiserum reacted well with TYLCV antigens but not with ToMoV antigens, while CabLCV antiserum reacted well with ToMoV antigens and weakly with TYLCV antigens. The results indicate that polyclonal antisera prepared to expressed begomovirus coat proteins were useful for the detection of begomoviruses in an array of assays.

Tobacco plants (Nicotiana tabacum 'Xanthi') were transformed with a binary vector containing the coat protein gene of tomato mottle begomo-virus (ToMoV) modified by the deletion of 30 nucleotides in the 5' end. The R(1) generation was screened for resistance to ToMoV by inoculation with viruliferous whiteflies. Fifteen days after inoculation, symptom development was recorded weekly for up to 120 days using a visual scale, and ToMoV infection was confirmed by polymerase chain reaction and enzyme-linked immunosorbent assay. The response to high inoculation levels of ToMoV varied and ranged from susceptibility to immunity. The transgene transcript was detected by northern blot analysis; however, the transgene product could not be detected by protein blot analysis using antisera reactive with ToMoV coat protein. The lack of detection of the transgene product in resistant plants suggests that it is not involved in eliciting the resistance response and that resistance may be mediated by the transgene transcript.

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