Quantitative analysis of the relationship between induction kinetics of chlorophyll fluorescence and function of genes in the cyanobacterium Synechocystis sp. PCC 6803.

We developed here the quantitative and objective method to analyze chlorophyll fluorescence from the cyanobacterium Synechocystis sp. PCC 6803 in the aim of systematic examination of gene function. The overall similarity of the chlorophyll fluorescence induction kinetics was evaluated for 499 mutants. Mutants of 333 genes showed the difference in the fluorescence kinetics from that of wild type, indicating the wide interaction of photosynthesis with other metabolisms. Hierarchical clustering of the similarity of the mutants enables us to group together the mutants having defect in the regulation of photosystem stoichiometry as well as those having defects in respiration or other functions. Furthermore, wild-type cells treated with inhibitors of respiration and mutants of genes involved in respiration shared similar induction kinetics. Apparently, quantitative comparison of the induction kinetics could be useful to analyze the function of genes as well as to predict the target sites of various chemicals.