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

Abstract 

In crucifers, the epidermal (papillar) cell of the stigma is uniquely specialized to allow the adhesion, hydration, and germination of pollen grains. In order to isolate genes expressed specifically in papillar cells, we compared the distribution of transcripts expressed in wild-type Brassica stigmas to those expressed in transgenic stigmas whose papillar cells were genetically ablated by expression of a cellular toxin under the control of a papillar cell-specific promoter. This analysis resulted in the isolation of several genes that are expressed specifically or predominantly in papillar cells. Antisense suppression indicated that one of the genes is required for efficient pollination in Brassica. The strategy described here should be applicable to the isolation of genes expressed specifically in any cell type that can be specifically ablated in transgenic plants.