ORIGINAL RESEARCH article

Front. Plant Sci.

Sec. Plant Biotechnology

Volume 16 - 2025 | doi: 10.3389/fpls.2025.1556957

In vitro demonstration and in planta characterization of a condensed, reverse TCA (crTCA) cycle

Provisionally accepted
Nathan  WilsonNathan Wilson1Caroline  Smith-MooreCaroline Smith-Moore1Yuan  XuYuan Xu2Brianne  EdwardsBrianne Edwards1Christophe  La HovaryChristophe La Hovary1Kai  LiKai Li1Denise  AslettDenise Aslett1Mikyoung  JiMikyoung Ji1Xiuli  LinXiuli Lin1Simina  VintilaSimina Vintila1Manuel  KleinerManuel Kleiner1De-Yu  XieDe-Yu Xie1Yair  Shachar-HillYair Shachar-Hill2Amy  Michele GrundenAmy Michele Grunden1*Heike  SederoffHeike Sederoff1*
  • 1North Carolina State University, Raleigh, United States
  • 2Michigan State University, East Lansing, Michigan, United States

The final, formatted version of the article will be published soon.

Plants employ the Calvin-Benson cycle (CBC) to fix atmospheric CO2 for the production of biomass. The flux of carbon through the CBC is limited by the activity and selectivity of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase (RuBisCO). Alternative CO2 fixation pathways that do not use RuBisCO to fix CO2 have evolved in some anaerobic, autotrophic microorganisms. Rather than modifying existing routes of carbon metabolism in plants, we have developed a synthetic carbon fixation cycle that does not exist in nature but is inspired by metabolisms of bacterial autotrophs. In this work, we build and characterize a condensed, reverse tricarboxylic acid (crTCA) cycle in vitro and in planta. We demonstrate that a simple, synthetic cycle can be used to fix carbon in vitro under aerobic and mesophilic conditions and that these enzymes retain activity when expressed transiently in planta. We then evaluate stable transgenic lines of Camelina sativa that have both phenotypic and physiologic changes. Transgenic C. sativa are shorter than controls with increased rates of photosynthetic CO2 assimilation and changes in photorespiratory metabolism. This first iteration of a build-test-learn phase of the crTCA cycle provides promising evidence that this pathway can be used to increase photosynthetic capacity in plants.

Keywords: Photosynthesis, CO2 fixation, Synthetic Biology, Camelina sativa, reverse TCA cycle, Carbon Capture

Received: 07 Jan 2025; Accepted: 13 May 2025.

Copyright: © 2025 Wilson, Smith-Moore, Xu, Edwards, Hovary, Li, Aslett, Ji, Lin, Vintila, Kleiner, Xie, Shachar-Hill, Grunden and Sederoff. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Amy Michele Grunden, North Carolina State University, Raleigh, United States
Heike Sederoff, North Carolina State University, Raleigh, United States

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