A Multi-Species Analysis Defines Anaplerotic Enzymes and Amides as Metabolic Markers for Ammonium Nutrition

Abstract

Nitrate and ammonium are the main nitrogen sources in agricultural soils. In the last decade, ammonium (NH4+), a double-sided metabolite, has attracted considerable attention by researchers. Its ubiquitous presence in plant metabolism and its metabolic energy economy for being assimilated contrast with its toxicity when present in high amounts in the external medium. Plant species can adopt different strategies to maintain NH4+ homeostasis, as the maximization of its compartmentalization and assimilation in organic compounds, primarily as amino acids and proteins. In the present study, we report an integrative metabolic response to ammonium nutrition of seven plant species, belonging to four different families: Gramineae (ryegrass, wheat, Brachypodium distachyon), Leguminosae (clover), Solanaceae (tomato), and Brassicaceae (oilseed rape, Arabidopsis thaliana). We use principal component analysis (PCA) and correlations among metabolic and biochemical data from 40 experimental conditions to understand the whole-plant response. The nature of main amino acids is analyzed among species, under the hypothesis that those Asn-accumulating species will show a better response to ammonium nutrition. Given the provision of carbon (C) skeletons is crucial for promotion of the nitrogen assimilation, the role of different anaplerotic enzymes is discussed in relation to ammonium nutrition at a whole-plant level. Among these enzymes, isocitrate dehydrogenase (ICDH) shows to be a good candidate to increase nitrogen assimilation in plants. Overall, metabolic adaptation of different carbon anaplerotic activities is linked with the preference to synthesize Asn or Gln in their organs. Lastly, glutamate dehydrogenase (GDH) reveals as an important enzyme to surpass C limitation during ammonium assimilation in roots, with a disparate collaboration of glutamine synthetase (GS).

A Mathematical Model for Characterizing the Biomass and the Physiological/Biochemical Indicators of Salvia miltiorrhiza Based on Growth-Defense Tradeoff

“…By Lasso analysis ( Figure 5 and Table 2 ), GS( x 7 ) and GDH( x 11 ) were positively correlated with biomass ( Table 3 ), indicating that GS( x 7 ) and GDH( x 11 ) were the main substrate in the seedling stage facilitate protein synthesis with amino acids and were conducive to coordinate C metabolism (Kaur et al, 2006 ), which was consistent with the rapid assimilation of N in early growth and laid the foundation for high rate C assimilation in later growth stages (Salehin et al, 2019 ; Gonzíalez-Moro et al, 2021 ; Wei et al, 2021 ). GS( x 7 ) was responsible for primary NH assimilation as well as germination, and elevating of GS( x 7 ) in leaves contributed to the conversion of inorganic NH to organic N (Lea and Morot-Gaudry, 2001 ).…”

“…GS( x 7 ) was responsible for primary NH assimilation as well as germination, and elevating of GS( x 7 ) in leaves contributed to the conversion of inorganic NH to organic N (Lea and Morot-Gaudry, 2001 ). There was a positive correlation between GDH( x 11 ) and total amino acid content in the root system (Gonzíalez-Moro et al, 2021 ). When GDH( x 11 ) was sufficiently induced in leaves, it would indicated substrate specificity in plants with other enzymes.…”

“…But with a large increase in the reduction of NH from NO , a sustained raising in GDH amination activity will inhibit GLS, GS, and GOGAT activities. Thus, GLS, GS, and GOGAT have a positive influence on biomass accumulation, while GDH has a bidirectional effect on biomass accumulation (Liang et al, 2018 ; Salehin et al, 2019 ; Gonzíalez-Moro et al, 2021 ; Wei et al, 2021 ). Many soluble proteins are crucial components of enzymes.…”

“…In the competition of biotic and abiotic stresses, the activities of enzymes, such as GS, GDH, NR, GOGAT, NiR, and GLS, as well as the soluble protein content, are considerable indicators of the N metabolic (Salehin et al, 2019 ; Gonzíalez-Moro et al, 2021 ; Wei et al, 2021 ). The enzymatic activities of superoxide dismutase (SOD), peroxidase (POD), catalase(CAT), proline (Pro), phenylalanine ammonialyase (PAL), and malondialdehyde (MDA) are commonly used to characterize defense responses (Jaafar et al, 2012 ; Farooq et al, 2020 ; Sarker and Oba, 2020 ; Zaheer et al, 2020 ).…”

Mathematical Model of Physiological and Biochemical Indexes to Plant Growth–Defense Tradeoff in Salvia Miltiorrhiza

“…GS and GOGAT can promote the synthesis of amino acids. GDH inhibit the synthesis of amino acids, but the synergistic effect of GDH and GS can also promote the synthesis of amino acids [9,10,11]. Then GS, GOGAT have appositive effect on biomass synthesis, while GDH has a two way effect.…”