Analysis of companion cell and phloem metabolism using a transcriptome-guided model of Arabidopsis metabolism

Hunt H, Brüggen N, Galle A, Vanderauwera S, Frohberg C, Fernie AR, Sonnewald U, Sweetlove LJ (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Plant Physiology American Society of Plant Biologists

DOI: 10.1093/plphys/kiad154

Abstract

Companion cells and sieve elements play an essential role in vascular plants, and yet the details of the metabolism that underpins their function remain largely unknown. Here, we construct a tissue-scale flux balance analysis (FBA) model to describe the metabolism of phloem loading in a mature Arabidopsis (Arabidopsis thaliana) leaf. We explore the potential metabolic interactions between mesophyll cells, companion cells, and sieve elements based on the current understanding of the physiology of phloem tissue and through the use of cell type-specific transcriptome data as a weighting in our model. We find that companion cell chloroplasts likely play a very different role to mesophyll chloroplasts. Our model suggests that, rather than carbon capture, the most crucial function of companion cell chloroplasts is to provide photosynthetically generated ATP to the cytosol. Additionally, our model predicts that the metabolites imported into the companion cell are not necessarily the same metabolites that are exported in phloem sap; phloem loading is more efficient if certain amino acids are synthesized in the phloem tissue. Surprisingly, in our model predictions, the proton-pumping pyrophosphatase (H+-PP(i)ase) is a more efficient contributor to the energization of the companion cell plasma membrane than the H+-ATPase.

Authors with CRIS profile

Nico Brüggen Lehrstuhl für Biochemie Uwe Sonnewald Lehrstuhl für Biochemie

Involved external institutions

Max-Planck-Institut für molekulare Pflanzenphysiologie / Max Planck Institute of Molecular Plant Physiology DE Germany (DE) BASF Belgium Coordination Center BE Belgium (BE) University of Oxford GB United Kingdom (GB)

How to cite

APA:

Hunt, H., Brüggen, N., Galle, A., Vanderauwera, S., Frohberg, C., Fernie, A.R.,... Sweetlove, L.J. (2023). Analysis of companion cell and phloem metabolism using a transcriptome-guided model of Arabidopsis metabolism. Plant Physiology. https://doi.org/10.1093/plphys/kiad154

MLA:

Hunt, Hilary, et al. "Analysis of companion cell and phloem metabolism using a transcriptome-guided model of Arabidopsis metabolism." Plant Physiology (2023).

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