Glsirt1-mediated deacetylation of GlCAT regulates intracellular ROS levels, affecting ganoderic acid biosynthesis in Ganoderma lucidum.

Lysine acetylation is a reversible, dynamic protein modification regulated by lysine acetyltransferases and deacetylases. However, in Basidiomycetes, the extent of lysine acetylation of nonhistone proteins remains largely unknown. Recently, we identified the deacetylase Glsirt1 as a key regulator of the biosynthesis of ganoderic acid (GA), a key secondary metabolite of Ganoderma lucidum. To gain insight into the characteristics, extent, and biological function of Glsirt1-mediated lysine acetylation in G. lucidum, we aimed to identify additional Glsirt1 substrates via comparison of acetylomes between wild-type (WT) and Glsirt1-silenced mutants. A large amount of Glsirt1-dependent lysine acetylation occurs in G. lucidum according to the results of this omics analysis, involving energy metabolism, protein synthesis, the stress response and other pathways. Our results suggest that GlCAT is a direct target of Glsirt1 and that the deacetylation of GlCAT by Glsirt1 reduces catalase activity, thereby leading to the accumulation of intracellular reactive oxygen species (ROS) and positively regulating the biosynthesis of GA. Our findings provide evidence for the involvement of nonhistone lysine acetylation in the biological processes of G. lucidum and help elucidate the involvement of important ROS signaling molecules in regulating physiological and biochemical processes in this organism. In conclusion, this proteomic analysis reveals a striking breadth of cellular processes affected by lysine acetylation and provides new nodes of intervention in the biosynthesis of secondary metabolites in G. lucidum.