Figure 2.

State Transition Analyzed by Low Temperature (77K) Emission Spectra of Chlorophyll Fluorescence and LHCII Phosphorylation in Wild-Type and pgrl1 Mutant C. reinhardtii Lines.

Cells were grown photoautotrophically in batch cultures under 200 μmol photons m⁻² s⁻¹ (HL; [A] to [E]) or 50 μmol photons m⁻² s⁻¹ (LL; [C]) in 2% CO₂-enriched air ([A], [C], and [D]) or air ([B], [C], and [E]). Samples were loaded at equal protein amounts based on Coomassie blue staining. LHCII proteins CP29, CP26, and LHCP11, which are phosphorylated in State 2 conditions but not in State 1, are shown (Fleischmann et al., 1999).

(A) and (B) 77K chlorophyll fluorescence emission spectra; wild-type progenitor line (black line); pgrl1 cells (gray line).

(C) E₆₈₅/E₇₁₀ chlorophyll fluorescence emission ratios measured in light-adapted pgrl1 (white bars) and wild-type (dark bars) lines grown under different light intensities and CO₂ concentrations.

(D) and (E) Immunodetection of phosphorylated LHCII using an antiphosphothreonine antibody in light-adapted pgrl1 and wild-type cells grown in HL in the presence of 2% CO₂-enriched air (D) or in the presence of air (E).