H-Shifts: The ²H fingerprint of plant metabolites to trace C metabolic shifts

Context

Quantifying carbon (C) metabolic fluxes in plants remains a major challenge, limiting our ability to link metabolism to plant performance and crop traits. Current approaches largely capture static metabolite levels rather than dynamic fluxes. This project proposes a novel proxy based on natural-abundance hydrogen stable isotopes (²H) in plant carbohydrates to infer central C metabolic activity. We hypothesize that ²H variation—at both whole-molecule and position-specific levels—reflects enzymatic isotope effects associated with key metabolic processes, including photosynthesis, photorespiration, and carbon partitioning. However, interpretation is currently constrained by the need to separate metabolic signals from hydrologic variability and to attribute isotope patterns to specific biochemical reactions.

Objectives

To advance the interpretation and application of whole-compound and position-specific ²H isotope patterns, the project will:

1. Develop approaches to isolate metabolic isotope signals from environmental water effects.
2. Apply a new modelling framework to quantify and partition biosynthetic isotope fractionation.
3. Test the functional relevance of these signals by analyzing metabolic shifts during soybean domestication and breeding.

This work will establish hydrogen isotope signatures as integrative, time-resolved proxies of plant metabolic fluxes and evaluate their potential to predict agronomically important traits.