PUB - Publikationen an der Universität Bielefeld

Flavonol synthase (FLS) is a key enzyme for the formation of flavonols, which are a subclass of the flavonoids. FLS catalyses the conversion of dihydroflavonols to flavonols. The enzyme belongs to the 2-oxoglutarate-dependent dioxygenases (2-ODD) superfamily. We characterized theFLSgene family ofBrassica napusthat covers 13 genes, based on the genome sequence of theB. napuscultivar Express 617. The goal was to unravel whichBnaFLSgenes are relevant for seed flavonol accumulation in the amphidiploid speciesB. napus.TwoBnaFLS1homoelogs were identified and shown to encode bifunctional enzymes. Both exhibit FLS activity as well as flavanone 3-hydroxylase (F3H) activity, which was demonstratedin vivoandin planta. BnaFLS1-1and -2are capable of converting flavanones into dihydroflavonols and further into flavonols. Analysis of spatio-temporal transcription patterns revealed similar expression profiles ofBnaFLS1genes. Both are mainly expressed in reproductive organs and co-expressed with the genes encoding early steps of flavonoid biosynthesis. Our results provide novel insights into flavonol biosynthesis inB. napusand contribute information for breeding targets with the aim to modify the flavonol content in rapeseed.