Fast light changes promote distinct responses of plastid protein acetylation marks

Protein acetylation is a key recurring co- and posttranslational modification. How different types of acetylation respond to the same environmental stress is unknown. A member of the newly discovered family of plastid acetyltransferases (GNAT2), which is featuring both lysine- and N-terminal acetyltransferase activity, was used in this study to obtain a holistic multi-omics acetylation-dependent view of the acclimation of plants to short-term light changes. Characterization of the N-terminal acetylome reveals that both its yield and coverage remain unchanged between WT and gnat2 knockout mutant lines when they are subjected for two hours to high-light or dark conditions. Similarly, no differences in their transcriptome or adenylate energy charge oscillations were observed under the tested light conditions between the genotypes. However, the GNAT2-associated lysine acetylome turned out to be sensitive to light changes. Our data suggests that the lysine acetylome marks on proteins change more rapidly allowing the acclimation to the environmental condition, while N-terminal acetylation changes are associated to long term responses. Taken together, our data reveals unique strategies of plant acclimation to the different treatments involving lysine but not N-terminal acetylation activities for the responses to environmental changes.