Regulation of carbon fixation
Biological process enrichment analysis based on DEPs showed no significant change in the carbon fixation pathway at the protein level. However, both Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoribulokinase (PRK), involved in carbon fixation pathway, were dissociated from the GAPDH/CP12/PRK complex by the downregulated CP12, indicating the activation of GAPDH and PRK. Moreover, thioredoxin reductase (NTRC), which is associated with the activation of thioredoxins-regulated enzymes in carbon fixation pathway, was upregulated (Table S1). The good function of the carbon fixation pathway during photoinhibition was supported by the significantly increased carboxylase activity of ribulose bisphosphate carboxylase/oxygenase (Rubisco) (Fig. 3A). Further supporting this function, photosynthetic rate characterized by O2 evolution rate exhibited a typical photoinduction process followed by a normal level (Fig. 3A).