SIRT2-mediated deacetylation of Glutathione transferase alleviates oxidative damage and increases heat tolerance of Pleurotus ostreatus

Abstract

High-temperature stress (HS) is the most important environmental factor that affects crop growth. It seriously threatens agricultural production. Pleurotus ostreatus is cultivated in many parts of the world, and its growth is strongly affected by HS. In another study, we found that metabolic rearrangement occurred in HS, but the gene expression levels of some key enzymes remained unchanged. Therefore, in this study, we investigated the contribution of post-translational modification of proteins to HS resistance in P. ostreatus. Acetylation is a conserved and important post-translational modification of proteins in vivo, and its main function is to regulate metabolic processes. We found that the level of acetylation of P. ostreatus decreased under short-term HS treatment and increased as the duration of HS treatment increased. The acetylation omics showed that almost all metabolic enzymes were acetylated. Ten antioxidant-related proteins, four acetylated proteins, and one deacetylated protein (SIRT2) were screened and identified in the differentially modified group between heat stress and normal conditions. A low concentration of the SIRT family substrate NAM (1 mM) was added to decrease the intracellular acetylation level. We found that deacetylation under heat stress can improve the growth recovery ability of mycelia, matrix-degrading enzyme activity, and antioxidant content (NADPH and GSH). Deacetylation can also decrease the H2O2 level after heat stress. Further studies showed that SIRT2 increased the activity of GSTs by deacetylating GST1 66K, GST2 206K, and GST2 233K. We found that lysine acetylation occurred in P. ostreatus, and thus, we assessed the importance of the acetylation of non-histone proteins under HS.