Control of light-dependent behaviour in cyanobacteria by the second messenger cyclic di-GMP

Abstract

Nucleotide-derived signalling molecules control a wide range of cellular processes in all organisms. The bacteria-specific cyclic dinucleotide c-di-GMP plays a crucial role in regulating motility-to-sessility transitions, cell cycle progression, and virulence. Cyanobacteria are phototrophic prokaryotes that perform oxygenic photosynthesis and are widespread microorganisms that colonise almost all habitats on Earth. In contrast to photosynthetic processes which are well understood, the behavioural responses of cyanobacteria have rarely been studied in detail. Analyses of cyanobacterial genomes have revealed that they encode a large number of proteins that are potentially involved in the synthesis and degradation of c-di-GMP. Recent studies have demonstrated that c-di-GMP coordinates many different aspects of the cyanobacterial lifestyle, mostly in a light-dependent manner. In this review, we focus on the current knowledge of light-regulated c-di-GMP signalling systems in cyanobacteria. Specifically, we highlight the progress made in understanding the most prominent behavioural responses of the model cyanobacterial strains Thermosynechococcus vulcanus and Synechocystis sp. PCC 6803. We discuss why and how cyanobacteria extract crucial information from their light environment to regulate ecophysiologically important cellular responses. Finally, we emphasise the questions that remain to be addressed.

Substrate specificity and ecological significance of PstS homologs in phosphorus uptake in marine Synechococcus sp. WH8102

“…This arrangement is conserved in all Synechococcus clade III strains in the Cyanorak database. Generally, in bacteria, cyclic di-GMP is a universal signaling molecule governing survival strategy ( 35 ), while the MAPEG protein protects against oxidative and metabolic stress, especially heat and cold temperature stress ( 36 ). Similarly, phosphoacetyltransferase catalyzes the production of acetyl phosphate, which is known to act as a phosphodonor for response regulators ( 37 ).…”

Transcriptomic meta-analysis and functional validation identify genes linked to adaptation and involved in high-light acclimation in Synechocystis sp. PCC 6803

“…The accelerated growth of HL4 and HL5 seems to allow Synechocystis cells to increase in volume, which together with a rapid depletion of nutrients might have resulted in significant cell aggregation and sinking in these mutants. Cell aggregation is modulated by blue light-dependent c-di-GMP signaling in Synechocystis (Enomoto et al, 2023), and is believed and is believed to protect cells from HL protect cells from HL via selfshading (Conradi et al, 2019). But interestingly, HL3 carrying a point mutation in the gene sll0267 that has been implicated in c-di-GMP signaling by its GGDEF and EAL domains displays increased HL tolerance in the absence of cell aggregation.…”

The second messenger c-di-AMP controls natural competence via ComFB signaling protein

“…To rule out that the transformation deficiency observed in Δ dacA mutant (Fig. 1A) is due to a downstream effect on the intracellular c-di-GMP content, which is known to regulate motility-related functions (Mantovani et al 2023a; Enomoto et al 2023), we measured the c-di-GMP levels in Δ dacA during the day and the night phases (Fig. S11).…”