摘要：SummaryCyanobacteria are gaining importance both as hosts for photoautotrophic production of chemicals and as model systems for studies of diurnal lifestyle. The proteome and transcriptome of cyanobacteria have been closely examined under diurnal growth, whereas the downstream effects on the intermediary metabolism have not received sufficient attention. The present study focuses on identifying the cellular metabolites whose inventories undergo dramatic changes in a fast-growing cyanobacterium,Synechococcus elongatusPCC 11801. We identified and quantified 67 polar metabolites, whose inventory changes significantly during diurnal growth, with some metabolites changing by 100-fold. The Calvin-Benson-Bassham cycle intermediates peak at midday to support fast growth. The hitherto unexplored γ-glutamyl peptides act as reservoirs of amino acids. Interestingly, several storage molecules or their precursors accumulate during the dark phase, dispelling the notion that all biosynthetic activity takes place in the light phase. Our results will guide metabolic modeling and strain engineering of cyanobacteria.Graphical AbstractDisplay OmittedHighlights•We identify and quantify 67 polar intermediate metabolites in cyanobacteria via LC-MS•A number of metabolites show large variations during the diurnal cycle•Intermediates of the CBB cycle peak at midday, coinciding with peak in growth rate•Gamma-glutamyl dipeptides identified as new storage compounds that peak at dawn
