Silencing of an Agrobacterium Vitis Oncogene in a Petunia Hybrida Model System


Linqui Han

Date of Graduation

Summer 1999


Master of Science in Plant Science



Committee Chair

Laszlo Kovacs


I constructed two Agrobacterium binary plasmids that contain a partial sequence of the TA-iaaM oncogene under the transcriptional control of the 35S or the or the 19S promoter of Cauliflower mosaic virus (CaMV). Using the leaf disk transformation technique, I introduced the T-DNAs of these binary vectors individually into transgenic Petunia hybrida plants that expressed a full-length copy of the iaaM gene under the CaMV 35S promoter. The expression of this full-length iaaM gene was mitotically stable, as evidenced by the maintenance of the auxin overproduction phenotype in transgenic plants that were regenerated in tissue culture. The introduction of the partial iaaM constructs resulted in 80 double-transformed plants, 14 of which reverted to wild-type phenotype, and are likely to be silencers of the full-length iaaM construct. All 14 of these revertants were double-transformed with the partial iaaM construct that was transcribed from the 35S promoter. These results suggest that the silencing of the full-length iaaM requires homology in the promoter region, and probably occurs at the level of transcription.

Subject Categories

Plant Sciences


© Linqui Han