emilio.villar.alegria@hu-berlin.de, tsu-wei.chen@hu-berlin.de

Understanding how plants acclimate their photosynthetic capacity to fluctuating environments is essential for developing crop varieties for future climatic conditions. Here, we propose a theoretical model of photosynthetic protein turnover to explain photosynthetic acclimation to light and temperature. This model considers the effects of light and temperature on the synthesis and degradation rate of photosynthetic proteins in three functional pools: carboxylation, electron transport, and light harvesting.

Using this model, photosynthetic protein abundancies and carbon assimilation rate can be simulated in leaf from its emergence until senescence. To assess how breeding has affected photosynthetic acclimation, we conducted a series of parameterizing experiments in growth chamber with different combinations of varying and constant light and temperature conditions using 60 winter wheat (Triticum aestivum) genotypes covering the recent German breeding history.

The maximum carboxylation rate, maximum electron transport rate, and chlorophyll concentration were periodically estimated using a combination of gas exchange, chlorophyll fluorescence, and pigment content measurements. Additionally, this ground-truth information was correlated to leaf hyperspectral data to achieve non-destructively estimation of three protein pool dynamics with high throughput.

The experiments enabled us to adapt our theoretical model by refining it with genotype-specific data, ensuring accurate simulations of photosynthetic responses under the tested environmental conditions. The experimental results suggest that there is variability in the acclimation strategies of our genotype panel in response to the different light and temperature regimes.

This highlights the importance of incorporating dynamic environmental responses into breeding programs to optimize the photosynthetic performance and sustainability of crop production systems.