Arabidopsis thaliana expresses a second functional flavonol synthase.
Arabidopsis thaliana L. produces flavonoid pigments, i.e. flavonols, anthocyanidins and proanthocyanidins, from dihydroflavonol substrates. A small family of putative flavonol synthase (FLS) genes had been recognized in Arabidopsis, and functional activity was attributed only to FLS1. Nevertheless, other FLS activities must be present, because A. thalianafls1 mutants still accumulate significant amounts of flavonols. The recombinant FLSs and leucoanthocyanidin dioxygenase (LDOX) proteins were therefore examined for their enzyme activities, which led to the identification of FLS3 as a second active FLS. This enzyme is therefore likely responsible for the formation of flavonols in the ldox/fls1-2 double mutant. These double mutant and biochemical data demonstrate for the first time that LDOX is capable of catalyzing the in planta formation of flavonols.
Philipps-Universität Marburg, Institut für Pharmazeutische Biologie, Marburg/Lahn, Germany.
Anja
A
Preuss
Ralf
R
Stracke
Bernd
B
Weisshaar
Alexander
A
Hillebrecht
Ulrich
U
Matern
Stefan
S
Martens
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D044950:Flavanones / Q000737:chemistry / Q000378:metabolism; D044948:Flavonols / Q000096:biosynthesis / Q000737:chemistry; D017343:Genes, Plant; D008958:Models, Molecular; D009154:Mutation; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
D029681:Arabidopsis Proteins; D044950:Flavanones; D044948:Flavonols; D010940:Plant Proteins; D011994:Recombinant Proteins; D010088:Oxidoreductases; D010105:Oxygenases; C105763:leucoanthocyanidin dioxygenase; C085313:flavonol synthase; C005273:naringenin