Phosphoenolpyruvate Carboxylase Dynamics in Plant Systems

Phosphoenolpyruvate carboxylase (PEPC) is a pivotal enzyme that catalyses the β-carboxylation of phosphoenolpyruvate to oxaloacetate, thereby linking carbon fixation, primary metabolism and stress adaptation in plants. Beyond its canonical roles in C4 and crassulacean acid metabolism (CAM) photosynthesis, PEPC contributes to anaplerotic replenishment of tricarboxylic acid cycle intermediates, nitrogen assimilation and organic acid export from roots. The enzyme’s activity is finely tuned through reversible phosphorylation by PEPC kinase (PPCK), monoubiquitination and metabolite effectors, enabling rapid acclimation to diurnal cycles, nutrient availability and abiotic stresses. Gene family expansion across angiosperms has yielded plant-type (PTPC) and bacterial-type (BTPC) isoforms with distinct kinetic properties and regulatory domains, while tissue-specific expression patterns underpin developmental programmes from pollen maturation to seed filling. Recent advances in genomics, structural biology and transgenic approaches have elucidated the molecular basis of allosteric control, isoform interplay and promoter-level regulation. Understanding PEPC dynamics offers routes to improve water-use efficiency, crop resilience and carbon–nitrogen balance under changing climates.

Research from Nature Portfolio

A genome-wide survey in soybean identified ten PEPC genes distributed across two subfamilies corresponding to PTPC and BTPC lineages. Phylogenetic analysis revealed conserved motifs and exon–intron structures that reflect ancient duplication events. Promoter interrogation uncovered cis-elements responsive to phytohormones and abiotic stresses, with several GmPEPCs being strongly induced by aluminium toxicity, cold, osmotic and salt challenges. Enzyme assays confirmed that selected isoforms exhibit enhanced activity under these treatments, underlining a direct role in stress tolerance. This comprehensive characterisation establishes a framework for functional dissection of PEPC contributions to carbon–nitrogen interactions and provides candidate genes for engineering improved stress adaptation in legumes.

Phosphoenolpyruvate Carboxylase Dynamics in Plant Systems publication trend

The graph below shows the total number of articles in phosphoenolpyruvate carboxylase dynamics in plant systems across all publications each year (not limited to Nature Index journals).

Technical terms

Phosphoenolpyruvate Carboxylase (PEPC): A cytosolic enzyme that fixes CO₂ into oxaloacetate, linking glycolysis to the tricarboxylic acid cycle and supporting diverse metabolic pathways.

PEPC Kinase (PPCK): A calcium-independent protein kinase that phosphorylates PEPC on a conserved serine residue, modulating its sensitivity to allosteric inhibitors and activators.

Plant-type PEPC (PTPC) and Bacterial-type PEPC (BTPC): Two evolutionary classes of PEPC subunits; PTPCs form homotetramers subject to regulation by phosphorylation and metabolites, whereas BTPCs associate with PTPCs to form heteromeric complexes with distinct kinetics.

Anaplerotic Reaction: A metabolic process that replenishes intermediate compounds of a pathway, here referring to PEPC’s role in maintaining tricarboxylic acid cycle flux under varying physiological conditions.

References

1. Identification and Analysis of PEPC Gene Family Reveals Functional Diversification in Orchidaceae and the Regulation of Bacterial-Type PEPC. International Journal of Molecular Sciences (2024).
2. Silencing of SbPPCK1-3 Negatively Affects Development, Stress Responses and Productivity in Sorghum. Plants (2023).
3. Genome-wide Analysis of Phosphoenolpyruvate Carboxylase Gene Family and Their Response to Abiotic Stresses in Soybean. Scientific Reports (2016).