Delila (del), a regulatory gene of Antirrhinum, alters anthocyanin pigmentation when introduced into two Solanaceous species. In tomato, pigmentation in vegetative tissues is strongly increased while in tobacco, intensification of pigment is restricted to flowers. Although del transcripts are ubiquitous in the transgenic plants, transcript levels of host anthocyanin biosynthetic genes are only increased in pigmented regions. Constructs carrying the maize transposon Ac, inserted at the 3' end of the 35S promoter prior to the start of translation of the dal gene, give variegated leaves in tomato, suggesting that del acts cell-autonomously and that it may be used as a phenotypic marker. In Arabidopsis, del has no strong phenotypic effects, suggesting that del may not be able to function effectively in all plant hosts.