Molecular characterization of the anthocyanidin synthase gene in Forsythiax intermedia reveals organ-specific expression during flower development

The study of the anthocyanidin synthase (ANS) gene, one of the late structu ral genes in the anthocyanin pathway, was undertaken in Forsythia x interme dia cv.'Spring Glory'. Previous molecular and biochemical studies had demon strated expression and activity of genes and enzymes upstream of ans. The a ns gene was cloned and shown to be present in two copies in the Forsythia g enome. Expression analyses carried out on flower organs showed that ans was expressed exclusively in anthocyanin-containing sepals and not in anthocya ninless anthers and petals. ans expression in sepals showed induction of tr anscription at early flower developmental stages. Inspection of the tms pro moter region as far as 790 bp upstream of the start codon revealed several potential DNA-protein binding motifs. The results from this paper. combined with previous data, show that the lack of ans expression should be the maj or cause of the absence of anthocyanins in Forsythia petals, thus providing directions for genetic engineering of Rower color in this ornamental speci es. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.