The invention includes modified Mazus chalcone synthase (CHS) nucleic acids, which encode a modified chalcone synthase that has alanine instead of cysteine at the 165^th amino acid of Mazus CHS and either glycine or lysine instead of methionine at the 138^th amino acid of Mazus CHS. The property of the encoded modified Mazus CHS is characterized by its dominant-negative inhibition of CHS. The invention also includes plants having at least one cell expressing the modified Mazus CHS. Such plants are characterized by the decreased content of anthocyanins. The invention also includes vectors comprising at least a portion of the modified Mazus CHS nucleic acids. The invention also includes methods using such vectors for producing plants having the decreased content of anthocyanins.