A study on the dynamic features of photosystem stoichiometry: Accomplishments and problems for future studies

Our study on the regulation by light of photosystem stoichiometry in cyanophytes is briefly reviewed here. It can be summarized as follows: Adjustment of photosystem stoichiometry results in optimization of photosynthetic efficiency under the prevailing light-growth conditions. Photosystem (PS) I is primarily affected, increasing or decreasing, relative to PS II. The regulation of PS I synthesis appears to be at the translation or the post-translational level. The regulation is probably governed by changes in the redox level of the electron transport components, most probably at Cyt b(6) in the Cyt b(6)-fcomplex. Our results to date are at the physiological level, but they have raised many questions and provided suggestions for future directions in exploring the mechanism of regulation, some of which are discussed in this perspective.