| Title: | Premature and ectopic anthocyanin formation by silencing of anthocyanidin reductase in strawberry (Fragaria x ananassa) |
| Author(s): | Fischer TC; Mirbeth B; Rentsch J; Sutter C; Ring L; Flachowsky H; Habegger R; Hoffmann T; Hanke MV; Schwab W; |
| Address: | "Plant Biochemistry and Physiology, Ludwig-Maximilians-University Munich, Grosshadernerstr 2-4, D-82152, Planegg-Martinsried, Germany. Julius Kuhn-Institute - Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Horticultural and Fruit Crops, Pillnitzer Platz 3a, 01326 Pillnitz, Dresden, Germany. Biotechnology of Natural Products, Technical University Munich (TUM), Liesel-Beckmann-Str 1, D-85354, Freising, Germany" |
| ISSN/ISBN: | 1469-8137 (Electronic) 0028-646X (Linking) |
| Abstract: | "Strawberry (Fragaria x ananassa) is a fruit crop with a distinct biphasic flavonoid biosynthesis. Whereas, in the immature receptacle, high levels of proanthocyanidins accumulate, which are associated with herbivore deterrence and pathogen defense, the prominent color-giving anthocyanins are primarily produced in ripe 'fruits' helping to attract herbivores for seed dispersal. Here, constitutive experimental down-regulation of one branch of proanthocyanidin biosynthesis was performed. As a result, the proportion of epicatechin monomeric units within the proanthocyanidin polymer chains was reduced, but this was not the case for the epicatechin starter unit. Shortened chain lengths of proanthocyanidins were also observed. All enzymatic activities for the production of color-giving anthocyanins were already present in unripe fruits at levels allowing a striking red anthocyanin phenotype in unripe fruits of the RNAi silencing lines. An immediately recognizable phenotype was also observed for the stigmata of flowers, which is another epicatechin-forming tissue. Thus, the down-regulation of anthocyanidin reductase (ANR) induced a redirection of the proanthocyanidin pathway, leading to premature and ectopic anthocyanin biosynthesis via enzymatic glycosylation as the alternative pathway. This redirection is also seen in flavonol biosynthesis, which is paralleled by higher pollen viability in silencing lines. ANRi transgenic lines of strawberry provide a versatile tool for the study of the biological functions of proanthocyanidins" |
| Keywords: | "Down-Regulation Flavonoids/biosynthesis Fragaria/genetics/*metabolism Fruit/genetics/metabolism Gene Expression Regulation, Plant Gene Silencing Oxidoreductases/genetics/metabolism Plant Proteins/genetics/metabolism Pollen/genetics/physiology Proanthocyan;" |
| Notes: | "MedlineFischer, Thilo C Mirbeth, Beate Rentsch, Judith Sutter, Corina Ring, Ludwig Flachowsky, Henryk Habegger, Ruth Hoffmann, Thomas Hanke, Magda-Viola Schwab, Wilfried eng Research Support, Non-U.S. Gov't England 2013/10/15 New Phytol. 2014 Jan; 201(2):440-451. doi: 10.1111/nph.12528. Epub 2013 Oct 1" |
