Plant Physiol. PAM Fluorometers & Gas Exchange
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on February 7, 2008; 10.1104/pp.107.114280

OPEN ACCESS ARTICLE
This Article
Free via Open Access: OA
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow Supplemental Data
Right arrowOA All Versions of this Article:
146/4/1528    most recent
pp.107.114280v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Griesser, M.
Right arrow Articles by Schwab, W.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Griesser, M.
Right arrow Articles by Schwab, W.
Agricola
Right arrow Articles by Griesser, M.
Right arrow Articles by Schwab, W.

Received November 29, 2007
Accepted January 21, 2008

Redirection of flavonoid biosynthesis through the downregulation of an anthocyanidin glucosyltransferase in ripening strawberry (Fragaria x ananassa) fruit

Markus Griesser , Thomas Hoffmann , Mari Luz Bellido , Carlo Rosati , Barbara Fink , Robert Kurtzer , Asaph Aharoni , Juan Munoz-Blanco , and Wilfried Schwab *

Biomolecular Food Technology, Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany; Departamento de Bioquimica y Biologia Molecular, Edificio Severo Ochoa (C-6), Campus Universitario de Rabanales, Universidad de Cordoba, 14071 Cordoba, Spain; ENEA C.R. Trisaia, Department of Genetics and Genomics, 106 Km 419+500, I-75026 Rotondella (MT), Italy; Plant Research International, Business Units Cell Cybernetics and Genetics & Breeding, PO Box 16, 6700 AA, Wageningen, Netherlands

* Corresponding author; email: schwab{at}wzw.tum.de.

Strawberry (Fragaria x ananassa) fruit contains several anthocyanins that give the ripe fruits their attractive red color. The enzyme that catalyzes the formation of the first stable intermediate in the anthocyanin pathway is anthocyanidin-3-O-glucosyltransferase. A putative glycosyltransferase sequence (FaGT1) was cloned from a strawberry fruit cDNA library and the recombinant FaGT1 transferred UDP-glucose to anthocyanidins, and to a lesser extent, to flavonols, generating the respective 3-O-glucosides. Quantitative PCR revealed that transcripts of FaGT1 were almost undetectable in green fruits, but gene expression increased dramatically in both turning and ripe red fruit, corresponding closely to the accumulation of anthocyanins during fruit ripening. The expression of FaGT1 is fruit-associated and negatively regulated by auxin. To elucidate the in planta function of FaGT1, Agrobacterium tumefaciens cells harboring an intron-hairpin construct of a partial FaGT1 sequence were injected into mid-sized ripening fruits. In about one third of the injected fruits this led to a significant downregulation of FaGT1 transcript levels that corresponded to reduced concentrations of anthocyanin pigments in ripe strawberry fruits. In contrast, significant levels of epiafzelechin - formed by anthocyanidin reductase (ANR) from pelargonidin - were identified in FaGT1 silenced fruits, indicating competition of FaGT1 and FaANR for the common anthocyanidin substrate. Thus FaGT1 represents an important branching point enzyme as it is channeling the flavonoid pathway to anthocyanins. These results demonstrate a method to redirect the anthocyanin biosynthesis into flavan-3-ol production in order to increase the levels of bioactive natural products or modify pigments in plant tissues.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY THE PLANT CELL
Copyright © 2008 by the American Society of Plant Biologists