StSIRT1 regulates potato dormancy through deacetylation of peroxidase-like 3 at K37

Plants have evolved sophisticated defense systems to synchronize growth with environmental fluctuations, including the adaptive strategy of dormancy, an important agronomic trait. Nevertheless, the role of posttranslational modification of nonhistone proteins in dormancy regulation remains elusive. Here, we report that sirtuin (StSIRT1)–mediated deacetylation of peroxidase (StPRX3) suppresses peroxidase activity, culminating in potato ( Solanum tuberosum L.) dormancy release. The lysine deacetylase StSIRT1—suppressed by the dormancy regulator nicotinamide (NAM)—accumulates during dormancy release and negatively modulates StPRX3. Furthermore, lysine-37 (K37; K denotes lysine) in StPRX3 is essential for its direct interaction with StSIRT1. StSIRT1 interacts with StPRX3 to regulate the hydrogen peroxide (H ₂ O ₂ )–scavenging capacity of peroxidase by decreasing K37 acetylation levels. Notably, the StPRX3 ^K37R (K37→arginine, K37R; R denotes arginine) mutant suppresses peroxidase activity, leading to accelerated potato dormancy release. Our findings uncover an StSIRT1-StPRX3 cascade in dormancy regulation that activates peroxidase and reduces H ₂ O ₂ levels in potato, providing insights into the complex regulatory networks involved in dormancy.