Peer-Reviewed Journal Details
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Hummel, I.,Pantin, F.,Sulpice, R.,Piques, M.,Rolland, G.,Dauzat, M.,Christophe, A.,Pervent, M.,Bouteille, M.,Stitt, M.,Gibon, Y.,Muller, B.
2010
July
Arabidopsis thaliana plants acclimate to water deficit at low cost through changes of C usage; an integrated perspective using growth, metabolite, enzyme and gene expression analysis
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()
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154
(1)(1)
357
72
Growth and carbon (C) fluxes are severely altered in plants exposed to soil water deficit. Correspondingly, it has been suggested that plants under water deficit suffer from C shortage. In this study, we test this hypothesis in Arabidopsis thaliana by providing an overview of the response of growth, C balance, metabolites, enzymes of the central metabolism and a set of sugar responsive genes to a sustained soil water deficit. The results show that under drought, rosette relative expansion rate is decreased more than photosynthesis, leading to a more positive C balance, while root growth is promoted. Several soluble metabolites accumulate in response to soil water deficit, with K+ and organic acids as the main contributors to osmotic adjustment. Osmotic adjustment costs only few % of the daily photosynthetic C fixation. All C metabolites measured (not only starch and sugars but also organic acids and amino acids) show a diurnal turnover that often increased under water deficit suggesting these metabolites are readily available for being metabolized in situ or exported to roots. On the basis of 30 enzyme activities, no in-depth reprogramming of C metabolism was observed. Water deficit induces a shift of the expression level of a set of sugar responsive genes that is indicative of increased, rather than decreased, C availability. These results converge to show that the differential impact of soil water deficit on photosynthesis and rosette expansion results in an increased availability of C for the roots, an increased turnover of C metabolites, a low cost C-based osmotic adjustment, and that these responses are performed without major reformatting of the primary metabolism machinery.Growth and carbon (C) fluxes are severely altered in plants exposed to soil water deficit. Correspondingly, it has been suggested that plants under water deficit suffer from C shortage. In this study, we test this hypothesis in Arabidopsis thaliana by providing an overview of the response of growth, C balance, metabolites, enzymes of the central metabolism and a set of sugar responsive genes to a sustained soil water deficit. The results show that under drought, rosette relative expansion rate is decreased more than photosynthesis, leading to a more positive C balance, while root growth is promoted. Several soluble metabolites accumulate in response to soil water deficit, with K+ and organic acids as the main contributors to osmotic adjustment. Osmotic adjustment costs only few % of the daily photosynthetic C fixation. All C metabolites measured (not only starch and sugars but also organic acids and amino acids) show a diurnal turnover that often increased under water deficit suggesting these metabolites are readily available for being metabolized in situ or exported to roots. On the basis of 30 enzyme activities, no in-depth reprogramming of C metabolism was observed. Water deficit induces a shift of the expression level of a set of sugar responsive genes that is indicative of increased, rather than decreased, C availability. These results converge to show that the differential impact of soil water deficit on photosynthesis and rosette expansion results in an increased availability of C for the roots, an increased turnover of C metabolites, a low cost C-based osmotic adjustment, and that these responses are performed without major reformatting of the primary metabolism machinery.
1532-2548 (Electronic) 00
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=20631317 http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=20631317
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