GENETIC ABLATION OF FLOWERS IN TRANSGENIC ARABIDOPSIS

We have created transgenic Arabidopsis plants in which a gene encoding the cell-autonomous diphtheria toxin A chain (DT-A) was expressed und er the control of the LEAFY (LFY) promoter. This promoter is active bo th in emerging leaf primordia and young flowers, with the highest acti vity in flowers. The majority of LFY:DT-A plants had normal vegetative development but lacked flowers, demonstrating that relatively widespr ead activity of a promoter does not exclude its possible use for ablat ing selected tissues, as long as differences in activity levels betwee n different tissues are significant. We also found that flowers were r eplaced by empty bracts in LFY:DT-A plants, suggesting that flower-der ived signals normally suppress bract development in Arabidopsis.