The beet R locus encodes a new cytochrome P450 required for red betalain production.
Anthocyanins are red and violet pigments that color flowers, fruits and epidermal tissues in virtually all flowering plants. A single order, Caryophyllales, contains families in which an unrelated family of pigments, the betalains, color tissues normally pigmented by anthocyanins. Here we show that CYP76AD1 encoding a novel cytochrome P450 is required to produce the red betacyanin pigments in beets. Gene silencing of CYP76AD1 results in loss of red pigment and production of only yellow betaxanthin pigment. Yellow betalain mutants are complemented by transgenic expression of CYP76AD1, and an insertion in CYP76AD1 maps to the R locus that is responsible for yellow versus red pigmentation. Finally, expression of CYP76AD1 in yeast verifies its position in the betalain biosynthetic pathway. Thus, this cytochrome P450 performs the biosynthetic step that provides the cyclo-DOPA moiety of all red betacyanins. This discovery will contribute to our ability to engineer this simple, nutritionally valuable pathway into heterologous species.
Section of Molecular Cell and Developmental Biology, Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA.
Gregory J
GJ
Hatlestad
Rasika M
RM
Sunnadeniya
Neda A
NA
Akhavan
Antonio
A
Gonzalez
Irwin L
IL
Goldman
J Mitchell
JM
McGrath
Alan M
AM
Lloyd
D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000235:genetics* / Q000378:metabolism; D027461:Beta vulgaris / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D050858:Betalains / Q000378:metabolism*; D003116:Color; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D017343:Genes, Plant; D056426:Genetic Loci; D007527:Isoenzymes; D008969:Molecular Sequence Data; D010860:Pigments, Biological / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D015003:Yeasts / Q000235:genetics
D000872:Anthocyanins; D007527:Isoenzymes; D010860:Pigments, Biological; D010940:Plant Proteins; D050858:Betalains; D003577:Cytochrome P-450 Enzyme System