Genetic control of chalcone isomerase activity in flowers of Dianthus caryophyllus.
In flowers of Dianthus caryophyllus (carnation), the gene I is concerned with a discrete step in flavonoid biosynthesis, Genotypes with recessive (ii) alleles produce yellow flowers, which contain the chalcone isosalipurposide (naringenin-chalcone-2'-glucoside) as the major petal pigment, but in genotypes with wild-type alleles flavonols and anthocyanins can be formed and the flowers are white or red. Enzymatic measurements on petal extracts of four strains with different flower coloration revealed a clear correlation between accumulation of chalcone in recessive genotypes and deficiency of chalcone isomerase (E.C. 5.5.1.6) activity. From the chemogenetic and enzymological evidence it can be concluded that naringenin-chalcone is the first product of the synthesis of the flavonoid skeleton and that only the conversion of naringenin-chalcone to naringenin furnishes the substrate for the further reactions to flavonol and anthocyanin.
D002599:Chalcone / Q000031:analogs & derivatives; D047188:Chalcones; D055598:Chemical Phenomena; D002621:Chemistry; D002854:Chromatography, Paper; D003433:Crosses, Genetic; D005786:Gene Expression Regulation; D019753:Intramolecular Lyases; D007535:Isomerases / Q000235:genetics*; D010860:Pigments, Biological / Q000235:genetics*; D010944:Plants / Q000201:enzymology / Q000235:genetics*
D047188:Chalcones; D010860:Pigments, Biological; C027321:isosalipurposide; D002599:Chalcone; D007535:Isomerases; D019753:Intramolecular Lyases; C019865:chalcone isomerase