Synechocystis sp. PCC 6803 proteome response to P-deficiency

Lipid droplets (LDs) are well integrated into multiple facets of cellular physiology and potentially represent an effective platform for the engineering of heterologous metabolic pathways. LDs of higher plant chloroplasts, known as plastoglobules (PGs), are critical mediators of stress tolerance through dynamic and reversible changes to morphology and molecular composition, however the dynamics and functional role(s) of cyanobacterial LDs are almost wholly unknown. Owing to their endosymbiotic origin as the progenitors of plant chloroplasts, we showed that cyanobacterial LDs designated as “cyanoglobule” share common characteristics with PGs, including molecular composition, structure, and their response under stress condition. We have monitored the dynamic accumulation of LDs, their protein, and lipid composition in response to phosphate deprivation. We are the first to describe cyanoglobule core proteome and lipidome in S6803 and their dynamics under P-deficiency. Our results showed that cyanoglobule share broadly similar protein and lipid compositions with plant plastoglobule, pointing to a central hub of cell lipid-protein metabolism and common role in stress adaptation, which then indicated their evolutionary relationship although specific differences may underscore an expansion of functions among higher plant PGs.