Metabolic engineering of the serine/glycine network as a means to improve the nitrogen content of crops

• DOI: 10.1111/pbi.14495
• Publication Date: 2024-10-25T09:41:50Z
• Authors: Ruben Casatejada‐...; Alejandro Torres‐...; Armand D. Anoman; Nagaveni Budhagat...; Ester Pérez‐Lorences; Andrea Alcántara‐...; Sara Rosa‐Téllez; Leonardo Perez de...; Jochen Kumlehn; Alisdair R. Fernie; Jesús Muñoz‐Bertomeu; Roc Ros
• Keywords: Photorespiration; Serine hydroxymethyltransferase; Isoleucine; Amino acid synthesis; Metabolic pathway

Summary In plants, L‐serine (Ser) biosynthesis occurs through various pathways and is highly dependent on the atmospheric CO 2 concentration, especially in C 3 species, due to association of Glycolate Pathway Ser Biosynthesis (GPSB) with photorespiration. Characterization a second plant pathway, Phosphorylated (PPSB), revealed that it at crossroads carbon, nitrogen, sulphur metabolism. The PPSB comprises three sequential reactions catalysed by 3‐phosphoglycerate dehydrogenase (PGDH), 3‐phosphoSer aminotransferase (PSAT) phosphatase (PSP). was overexpressed plants exhibiting two different modes photosynthesis: Arabidopsis (C metabolism), maize 4 under ambient (aCO ) elevated (eCO growth conditions. Overexpression PGDH1 gene alone or , PSAT1 PSP1 combination increased levels but also essential amino acids threonine ), isoleucine, leucine, lysine, phenylalanine, methionine compared wild‐type. These increases translated into higher protein levels. Likewise, starch were PPSB‐overexpressing lines. maize, PPSB‐deficient lines obtained targeting using Cas9 endonuclease. We concluded expression male gametophyte required for viable pollen development. Maize overexpressing AtPGDH1 only displayed not both aCO eCO conditions, this significant rise nitrogen/carbon ratio. results suggest metabolic engineering crops could enhance nitrogen content, particularly upcoming conditions where activity GPSB limited.