Acclimation to elevated CO 2 affects the C/N balance by reducing de novo N-assimilation.

Autor: Krämer K; Institute of Biomaterials and Biomolecular Systems, Department of Plant Biotechnology, University of Stuttgart, Stuttgart, Germany., Kepp G; Institute of Biomaterials and Biomolecular Systems, Department of Plant Biotechnology, University of Stuttgart, Stuttgart, Germany., Brock J; Institute of Biomaterials and Biomolecular Systems, Department of Plant Biotechnology, University of Stuttgart, Stuttgart, Germany., Stutz S; Institute of Biomaterials and Biomolecular Systems, Department of Plant Biotechnology, University of Stuttgart, Stuttgart, Germany., Heyer AG; Institute of Biomaterials and Biomolecular Systems, Department of Plant Biotechnology, University of Stuttgart, Stuttgart, Germany.
Jazyk: angličtina
Zdroj: Physiologia plantarum [Physiol Plant] 2022 Jan; Vol. 174 (1), pp. e13615. Date of Electronic Publication: 2022 Jan 10.
DOI: 10.1111/ppl.13615
Abstrakt: Plants exposed to elevated atmospheric CO 2 concentrations show an increased photosynthetic activity. However, after prolonged exposure, the activity declines. This acclimation to elevated CO 2 is accompanied by a rise in the carbon-to-nitrogen ratio of the biomass. Hence, increased sugar accumulation and sequential downregulation of photosynthetic genes, as well as nitrogen depletion and reduced protein content, have been hypothesized as the cause of low photosynthetic performance. However, the reason for reduced nitrogen content in plants at high CO 2 is unclear. Here, we show that reduced photorespiration at increased CO 2 -to-O 2 ratio leads to reduced de novo assimilation of nitrate, thus shifting the C/N balance. Metabolic modeling of acclimated and non-acclimated plants revealed the photorespiratory pathway to function as a sink for already assimilated nitrogen during the light period, providing carbon skeletons for de novo assimilation. At high CO 2 , low photorespiratory activity resulted in diminished nitrogen assimilation and eventually resulted in reduced carbon assimilation. For the hpr1-1 mutant, defective in reduction of hydroxy-pyruvate, metabolic simulations show that turnover of photorespiratory metabolites is expanded into the night. Comparison of simulations for hpr1-1 with those for the wild type allowed investigating the effect of a perturbed photorespiration on N-assimilation.
(© 2021 The Authors. Physiologia Plantarum published by John Wiley & Sons Ltd on behalf of Scandinavian Plant Physiology Society.)
Databáze: MEDLINE
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