Fig. 4. EPYC1-mediated condensation of Rubisco has no negative impact on growth and photosynthesis.

a Fresh and dry weights of three T2 EPYC1-dGFP S2_Cr transgenic lines (Ep1−3) and an EPYC1-dGFP WT transformant (EpWT) (both in green) with their respective azygous segregants (Az1−3 and AzWT) (in grey). Plants were measured after 32 days of growth under 200 μmol photons m⁻² s⁻¹ light. The mean ± SEM are shown for n = 10−26 individual plants for each line. b Rosette expansion of S2_Cr and WT lines in (a). c Net CO₂ assimilation (A) based on intercellular [CO₂] (C_i) under saturating light (1500 μmol photons m⁻² s⁻¹). Values show the mean ± SEM of measurements made on individual leaves from individual rosettes (n = 5−8). d Variables derived from gas exchange data include maximum rate of Rubisco carboxylation (V_cmax), maximum electron transport rate (J_max), stomatal conductance (G_s), mesophyll conductance (G_m) and the net CO₂ assimilation rate at ambient concentrations of CO₂ normalised to Rubisco (A_Rubisco). Letters indicate significant difference (p < 0.05) of EpWT lines compared to Ep lines as determined by one-way ANOVA followed by Tukey’s honestly significant difference (HSD) post-hoc tests (a, d). e Algal CCM components required for enhancing photosynthesis. Generating a pyrenoid-like condensate in a plant chloroplast provides a platform for introducing bicarbonate (HCO₃⁻) channels/pumps at the chloroplast envelope (e.g. LCIA, shown in red)³⁴ and thylakoid membrane (e.g. BST1−3, shown in orange)³⁵, a lumenal carbonic anhydrase to convert HCO₃⁻ to CO₂ for release into the surrounding Rubisco condensate (CAH3, shown in blue)³⁶, mechanisms to capture CO₂ as HCO₃⁻ (LCIB and LCIC, shown in purple)^37,38 and traversing thylakoid membranes³³. Current models suggest that introduction of a functional biophysical CCM into a C3 plant could lead to productivity gains of up to 60% ^29–31. Source data are provided as a Source Data file.