Carbon Metabolism and the ROS Scavenging System Participate in Nostoc flagelliforme’s Adaptive Response to Dehydration Conditions through Protein Acetylation

Acetylation represents an extensively
occurring protein post-translational
modification (PTM) that plays a key role in many cellular physiological
and biochemical processes. However, studies on PTMs such as acetylation
of lysine (LysAc) in cyanobacteria are still rare. In this study,
a quantitative LysAc approach (acetylome) on the strains of Nostoc flagelliforme subjected to different dehydration
treatments was conducted. We observed that starch contents were significantly
accumulated due to dehydration treatments, and we identified 2474
acetylpeptides and 1060 acetylproteins based on acetylome analysis.
Furthermore, an integrative analysis was performed on acetylome and
nontargeted metabolism, and the results showed that many KEGG terms
were overlapped for both omics analyses, including starch and sucrose
metabolism, transporter activity, and carbon metabolism. In addition,
time series clustering was analyzed, and some proteins related to
carbon metabolism and the ROS scavenging system were significantly
enriched in the list of differentially abundant acetylproteins (DAAPs).
These protein expression levels were further tested by qPCR. A working
model was finally proposed to show the biological roles of protein
acetylation from carbon metabolism and the ROS scavenging system in
response to dehydration in N. flagelliforme. We highlighted that LysAc was essential for the regulation of key
metabolic enzymes in the dehydration stress response.