The TrAP / REn monodirectional promoter of Mungbean yellow mosaic geminivirus (MYMV) displays root-specific expression in transgenic tobacco

The TrAP / REn monodirectional promoter of Mungbean yellow mosaic virus (MYMV) comprises many root-specific motifs. The TrAP / REn promoter fused to the β-glucuronidase ( gus ) reporter gene was used to transform tobacco. Histochemical staining of various parts of seven transgenic plants showed a preferential root-specific expression pattern. Tobacco transformation with the TrAP gene under the transcriptional control of the TrAP / REn promoter yielded nine transgenic plants, of which six harboured the complete TrAP gene in the integrated T-DNAs. Transcript analysis indicated root tissue-specific expression of the TrAP gene. TrAP transgenic plants were phenotypically normal. Expression of the TrAP gene under its own promoter obviated the toxicity which was observed when the TrAP gene was expressed under the CaMV 35S promoter.