Animal cell-death suppressors Bcl-x(L) and Ced-9 inhibit cell death in tobacco plants

In plants, events similar to programmed cell death have been reported [1,2] , although little is known of their mechanisms at the molecular level. To i nvestigate the mechanism(s) involved, we overexpressed bcl-x(L), which enco des a mammalian suppressor of programmed cell death, in tobacco plants, und er the control of a strong promoter [3]. In plants expressing Bcl-x(L), cel l death induced by UV-B irradiation, paraquat treatment or the hypersensiti ve reaction (HR) to tobacco mosaic virus (TMV) infection was suppressed. Th e extent of suppression of cell death depended on the amount of Bcl-x(L) pr otein expressed, Similar enhanced resistance to cell death was found in tra nsgenic tobacco plants overexpressing the ced-9 gene, a Caenorhabditis eleg ans homolog of bcl-x(L) [4], indicating that Bcl-x(L) and Ced-9 can functio n to inhibit cell death in plants.