摘要N-terminal acetylation is one of the most common protein modifications in eukaryotes,and approxi-mately 40％of human and plant proteomes are acetylated by ribosome-associated N-terminal acetyl-transferase A(NatA)in a co-translational manner.However,the in vivo regulatory mechanism of NatA and the global impact of NatA-mediated N-terminal acetylation on protein fate remain unclear.Here,we identify Huntingtin Yeast partner K(HYPK),an evolutionarily conserved chaperone-like protein,as a positive regulator of NatA activity in rice.We found that loss of OsHYPK function leads to develop-mental defects in rice plant architecture but increased resistance to abiotic stresses,attributable to perturbation of the N-terminal acetylome and accelerated global protein turnover.Furthermore,we demonstrated that OsHYPK is also a substrate of NatA and that N-terminal acetylation of OsHYPK pro-motes its own degradation,probably through the Ac/N-degron pathway,which could be induced by abiotic stresses.Taken together,our findings suggest that the OsHYPK-NatA complex plays a critical role in coordinating plant development and stress responses by dynamically regulating NatA-mediated N-terminal acetylation and global protein turnover,which are essential for maintaining adaptive pheno-typic plasticity in rice.