Metabolomics reveals comprehensive reprogramming involving two independent metabolic responses of Arabidopsis to UV‐B light
Because of ever‐increasing environmental deterioration it is likely that the influx of UV‐B radiation (280–320 nm) will increase as a result of the depletion of stratospheric ozone. Given this fact it is essential that we better understand both the rapid and the adaptive responses of plants to UV‐B stress. Here, we compare the metabolic responses of wild‐type Arabidopsis with that of mutants impaired in flavonoid (transparent testa 4, tt4; transparent testa 5, tt5) or sinapoyl‐malate (sinapoylglucose accumulator 1, sng1) biosynthesis, exposed to a short 24‐h or a longer 96‐h exposure to this photo‐oxidative stress. In control experiments we subjected the genotypes to long‐day conditions as well as to 24‐ and 96‐h treatments of continuous light. Following these treatments we evaluated the dynamic response of metabolites including flavonoids, sinapoyl‐malate precursors and ascorbate, which are well known to play a role in cellular protection from UV‐B stress, as well as a broader range of primary metabolites, in an attempt to more fully comprehend the metabolic shift following the cellular perception of this stress. Our data reveals that short‐term responses occur only at the level of primary metabolites, suggesting that these effectively prime the cell to facilitate the later production of UV‐B‐absorbing secondary metabolites. The combined results of these studies together with transcript profiles using samples irradiated by 24‐h UV‐B light are discussed in the context of current models concerning the metabolic response of plants to the stress imposed by excessive UV‐B irradiation.
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Document Type: Research Article
Affiliations: 1: RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan 2: Max-Planck Institute for Molecular Plant Physiology, Potsdam-Golm 14476, Germany
Publication date: July 1, 2011