Stress-induced flavonoid biosynthesis and the antioxidant machinery of plants

There is a growing body of evidence that flavonoids do not primarily function as UV-B screening pigments in photoprotection. Recent findings support the idea that excess light stress, irrespective of the relative proportions of the solar wavebands reaching the leaf surface, up-regulates the biosynth...

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Bibliographic Details
Published in:Plant signaling & behavior 2011-05, Vol.6 (5), p.709-711
Main Authors: Fini, Alessio, Brunetti, Cecilia, Di Ferdinando, Martina, Ferrini, Francesco, Tattini, Massimiliano
Format: Article
Language:English
Subjects:
Addendum
antioxidants
Antioxidants - metabolism
behavior
Binding
Biology
Bioscience
biosynthesis
Calcium
Cancer
Cell
chloroplasts
Cycle
flavonoids
Flavonoids - biosynthesis
glycosides
homeostasis
Landes
leaves
Organogenesis
Plants - enzymology
Plants - metabolism
Proteins
radiation resistance
Stress, Physiological
Time Factors
tonoplast
vacuoles
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Summary:There is a growing body of evidence that flavonoids do not primarily function as UV-B screening pigments in photoprotection. Recent findings support the idea that excess light stress, irrespective of the relative proportions of the solar wavebands reaching the leaf surface, up-regulates the biosynthesis of dihydroxy B-ring-substituted flavonoid glycosides, as a consequence of and aimed at countering the generation of ROS. Intriguingly, the very conditions that lead to the inactivation of antioxidant enzymes can also up-regulate the biosynthesis of antioxidant flavonoids, which suggests flavonoids constituting a secondary ROS-scavenging system in plants exposed to severe/prolonged stress conditions. H 2 O 2 may diffuse out of the chloroplast at considerable rates and be transported to the vacuole, the storing site for flavonoids, by tonoplast intrinsic proteins, under severe excess light conditions. We suggest that the unanticipated key role of the vacuole in the ROS homeostasis might be mediated by flavonoids.
ISSN:1559-2316
1559-2324
1559-2324
DOI:10.4161/psb.6.5.15069