Deficiens is a floral homeotic gene of Antirrhinum majus, mutation of which results in transformation of petals to sepals and stamens to carpels. In a search for putative target genes, controlled by this regulatory locus, cDNA clones representing genes, that are expressed in wild type but not in the deficiens mutant flowers, were isolated by differential screening. The molecular structure and the expression pattern of one of these genes, tap2, is described. Tap2 is transiently and tissue-specifically expressed in the tapetum of the anthers. It encodes a 131 amino-acids-long protein with a hydrophobic N-terminus, displaying all characteristic features of a signal peptide. This indicates that the TAP2 protein may be secreted.