Use of genetically ablated stigmas for the isolation of genes expressed specifically in the stigma epidermis

In crucifers, the epidermal (papillar) cell of the sti-ma is uniquely speci alized to allow the adhesion, hydration, and germination of pollen grains. In order to isolate genes expressed specifically in papillar cells, we comp ared the distribution of transcripts expressed in wild-type Brassica stigma s to those expressed in transgenic stigmas whose papillar cells were geneti cally ablated by expression of a cellular toxin under the control of a papi llar cell-specific promoter. This analysis resulted in the isolation of sev eral genes that are expressed specifically or predominantly in papillar cel ls. Antisense suppression indicated that one of the genes is required for e fficient pollination in Brassica. The strategy described here should be app licable to the isolation of genes expressed specifically in any cell type t hat can be specifically ablated in transgenic plants.