The present invention provides the use of a regulatory gene Lc and encoded protein to alter the biosynthesis and accumulation of flavonoids including anthocyanins and condensed tannins in plants and plant tissues, particularly in alfalfa, white clover, and other forage legumes which are similar in lacking native condensed tannin accumulation in leaves. The identification of the effects of this gene in alfalfa provide a mechanism for altering flavonoid, anthocyanin and condensed tannin production in forage legumes and allows one to alter such levels to produce a variety of benefits in the field of agriculture, animal farming and food technology in general.