Genetic control of chalcone synthase activity in flowers of matthiola incana R.Br

Chalcone synthase activity was demonstrated in enzyme preparations from flowers of defined genotypes of Matthiola incana (stock). The product formed from 4-coumaroyl-CoA and malonyl-CoA was naringenin and not the isomeric chalcone, because chalcone isomerase was also present in the reaction mixture. Chalcone synthase activity could be detected only in flower extracts of genotypes with wild-type alleles at the locus f Thus, the interruption of the anthocyanin pathway in white flowering lines with recessive alleles (ff) of this gene is clearly due to a lack of this enzyme activity. Independent on the genetic state of the locus b which controls the formation of pelargonidin or cyanidin, respectively, in the flowers, 4-coumaroyl-CoA was the only suitable substrate for the condensation reaction.