Iñigo Saiz-Fernández1, Nuria De Diego2, Břetislav Brzobohatý3, Alberto Muñoz-Rueda4, Maite Lacuesta5. 1. Department of Plant Biology and Ecology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, E-01006, Vitoria-Gasteiz, Spain; Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR, CEITEC - Central European Institute of Technology, Phytophthora Research Centre, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, CZ-613 00, Brno, Czech Republic. Electronic address: inigo.saiz@ehu.es. 2. Department of Plant Biology and Ecology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, E-01006, Vitoria-Gasteiz, Spain; Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, CZ-783 71, Olomouc, Czech Republic. 3. Laboratory of Plant Molecular Biology, Institute of Biophysics AS CR, CEITEC - Central European Institute of Technology, Phytophthora Research Centre, Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, CZ-613 00, Brno, Czech Republic. 4. Department of Plant Biology and Ecology, Faculty of Sciences and Technology, University of the Basque Country UPV/EHU, E-48080, Leioa, Spain. 5. Department of Plant Biology and Ecology, Faculty of Pharmacy, University of the Basque Country UPV/EHU, E-01006, Vitoria-Gasteiz, Spain.
Abstract
Nitrogen (N) is an important regulator of photosynthetic carbon (C) flow in plants, and an adequate balance between N and C metabolism is needed for correct plant development. However, an excessive N supply can alter this balance and cause changes in specific organic compounds associated with primary and secondary metabolism, including plant growth regulators. In previous work, we observed that high nitrate supply (15 mM) to maize plants led to a decrease in leaf expansion and overall biomass production, when compared with low nitrate supply (5 mM). Thus, the aim of this work is to study how overdoses of nitrate can affect photosynthesis and plant development. The results show that high nitrate doses greatly increased amino acid production, which led to a decrease in the concentration of 2-oxoglutarate, the main source of C skeletons for N assimilation. The concentration of 1-aminocyclopropane-1-carboxylic acid (and possibly its product, ethylene) also rose in high nitrate plants, leading to a decrease in leaf expansion, reducing the demand for photoassimilates by the growing tissues and causing the accumulation of sugars in source leaves. This accumulation of sugars, together with the decrease in 2-oxoglutarate levels and the reduction in chlorophyll concentration, decreased plant photosynthetic rates. This work provides new insights into how high nitrate concentration alters the balance between C and N metabolism, reducing photosynthetic rates and disrupting whole plant development. These findings are particularly relevant since negative effects of nitrate in contexts other than root growth have rarely been studied.
Nitrogen (n class="Chemical">N) is an important regulator of photosynthetic carbon (C) flow in plants, and an adequate balance between N and C metabolism is needed for correct plant development. However, an excessive N supply can alter this balance and cause changes in specific organic compounds associated with primary and secondary metabolism, including plant growth regulators. In previous work, we observed that high nitrate supply (15 mM) to maize plants led to a decrease in leaf expansion and overall biomass production, when compared with low nitrate supply (5 mM). Thus, the aim of this work is to study how overdoses of nitrate can affect photosynthesis and plant development. The results show that high nitrate doses greatly increased amino acid production, which led to a decrease in the concentration of 2-oxoglutarate, the main source of C skeletons for N assimilation. The concentration of 1-aminocyclopropane-1-carboxylic acid (and possibly its product, ethylene) also rose in high nitrate plants, leading to a decrease in leaf expansion, reducing the demand for photoassimilates by the growing tissues and causing the accumulation of sugars in source leaves. This accumulation of sugars, together with the decrease in 2-oxoglutarate levels and the reduction in chlorophyll concentration, decreased plant photosynthetic rates. This work provides new insights into how high nitrate concentration alters the balance between C and N metabolism, reducing photosynthetic rates and disrupting whole plant development. These findings are particularly relevant since negative effects of nitrate in contexts other than root growth have rarely been studied.
Authors: Tamara Corcobado; Ivan Milenković; Iñigo Saiz-Fernández; Tomáš Kudláček; Roman Plichta; Tomáš Májek; Aneta Bačová; Henrieta Ďatková; László Benedek Dálya; Miloš Trifković; Davide Mureddu; Vladimír Račko; Monika Kardošová; Jaroslav Ďurkovič; Roman Rattunde; Thomas Jung Journal: J Fungi (Basel) Date: 2022-03-14