{"entity": "publication", "iuid": "e6cd9d7785c54dada0777d5e5f839bf9", "timestamp": "2026-07-22T23:48:57.337Z", "links": {"self": {"href": "https://publications.scilifelab.se/publication/e6cd9d7785c54dada0777d5e5f839bf9.json"}, "display": {"href": "https://publications.scilifelab.se/publication/e6cd9d7785c54dada0777d5e5f839bf9"}}, "title": "Anaplerotic flux into the Calvin-Benson cycle: hydrogen isotope evidence for in vivo occurrence in C3 metabolism.", "authors": [{"family": "Wieloch", "given": "Thomas", "initials": "T", "orcid": "0000-0001-9162-2291", "researcher": {"href": "https://publications.scilifelab.se/researcher/ae51002869054ad981fde0c6b4d9d047.json"}}, {"family": "Augusti", "given": "Angela", "initials": "A", "orcid": "0000-0002-9591-693X", "researcher": {"href": "https://publications.scilifelab.se/researcher/02e12e062b23482993b5840a1ffe5ad2.json"}}, {"family": "Schleucher", "given": "J\u00fcrgen", "initials": "J", "orcid": "0000-0002-4815-3466", "researcher": {"href": "https://publications.scilifelab.se/researcher/ad2a0d8c63a7453e9dda23cf94b9e202.json"}}], "type": "journal article", "published": "2022-01-12", "journal": {"title": "New Phytol.", "issn": "1469-8137", "issn-l": "0028-646X"}, "abstract": "As the central carbon uptake pathway in photosynthetic cells, the Calvin-Benson cycle is among the most important biochemical cycles for life on Earth. A carbon flux of anaplerotic origin (i.e. through the chloroplast-localized oxidative branch of the pentose phosphate pathway) into the Calvin-Benson cycle was proposed recently. Here, we measured intramolecular deuterium abundances in leaf starch of Helianthus annuus grown at varying ambient CO2 concentrations, Ca . Additionally, we modelled deuterium fractionations expected for the anaplerotic pathway and compared modelled with measured fractionations. We report deuterium fractionation signals at H1 and H2 of starch glucose. Below a Ca change point, these signals increase with decreasing Ca consistent with modelled fractionations by anaplerotic flux. Under standard conditions (Ca = 450 ppm corresponding to intercellular CO2 concentrations, Ci , of 328 ppm), we estimate negligible anaplerotic flux. At Ca = 180 ppm (Ci = 140 ppm), more than 10% of the glucose-6-phosphate entering the starch biosynthesis pathway is diverted into the anaplerotic pathway. In conclusion, we report evidence consistent with anaplerotic carbon flux into the Calvin-Benson cycle in vivo. We propose the flux may help to: maintain high levels of ribulose 1,5-bisphosphate under source-limited growth conditions to facilitate photorespiratory nitrogen assimilation required to build-up source strength; and counteract oxidative stress.", "doi": "10.1111/nph.17957", "pmid": "35020197", "labels": {"Swedish NMR Centre": "Collaborative"}, "xrefs": [], "notes": [], "created": "2022-01-17T13:31:57.195Z", "modified": "2025-10-17T13:03:55.133Z"}