Figure 7.

Adaptation of the Photosynthetic Apparatus of pgrl1 and Wild-Type C. reinhardtii Cells to a Switch from High to Low CO₂.

Cells were cultivated autotrophically in photobioreactors operated as turbidostats at a constant biomass concentration (≈1.5 × 10⁶ cells mL⁻¹) in the presence of 2% CO₂-enriched air under a light intensity of 500 μmol photons m⁻² s⁻¹. Upon 48 h stabilization, cultures were shifted to air CO₂ levels (0 h). Samples were taken at 0, 2, 4, 6, and 24 h after the shift in order to perform immunodetection ([A] and [B]) and functional analysis ([C] to [E]).

(A) and (B) Different antibodies raised against PsaC (PSI), PsbD (PSII), PGRL1, NDA2, AOX1 (AOX), COXIIb (COXII), FeSOD, and FLVs were used to decorate immunoblots. Samples were loaded at equal total proteins amounts based on Coomassie blue staining (Control).

(C) PSI/PSII ratio determined from ECS measurements.

(D) Light-dependent O₂ uptake rates were measured using a MIMS in the presence of [¹⁸O]-enriched O₂ as in Figure 5; corresponding O₂ production rates are shown as Supplemental Figure 5.

(E) Growth performances measured as dilution rates used to maintain the culture at a constant biomass concentration; pgrl1 (gray line) and wild-type control (black line).