Downregulation of N-terminal acetylation triggers ABA-mediated drought responses in Arabidopsis

N-terminal acetylation (NTA) catalysed by N-terminal acetyltransferases (Nats) is among the most common protein modifications in eukaryotes, but its significance is still enigmatic. Here we characterize the plant NatA complex and reveal evolutionary conservation of NatA biochemical properties in higher eukaryotes and uncover specific and essential functions of NatA for development, biosynthetic pathways and stress responses in plants. We show that NTA decreases significantly after drought stress, and NatA abundance is rapidly downregulated by the phytohormone abscisic acid. Accordingly, transgenic downregulation of NatA induces the drought stress response and results in strikingly drought resistant plants. Thus, we propose that NTA by the NatA complex acts as a cellular surveillance mechanism during stress and that imprinting of the proteome by NatA is an important switch for the control of metabolism, development and cellular stress responses downstream of abscisic acid. N-terminal acetylation is a common protein modification in eukaryotes. Here the authors show that in Arabidopsis , N-terminal acetylation is decreased by drought stress, that abundance of an N-terminal acetyltransferase is reduced by abscisic acid and that constitutive downregulation can confer drought resistance.