摘要
Ubiquitination is an important protein post-translational modification,which is involved in various cellular processes in higher plants,and U-box E3 ligases play important roles in diverse functions in eukaryotes.Here,we describe the functions ofArabidopsis thaliana PUB19(AtPUB19),which we demonstrated in an in vitro assay to encode a U-box type E3 ubiquitin ligase.AtPUB19 was up-regulated by drought,salt,cold,and abscisic acid(ABA).Down-regulation of AtPUB19 led to hypersensitivity to ABA,enhanced ABA-induced stomatal closing,and enhanced drought tolerance,while AtPUB19 overexpression resulted in the reverse phenotypes.Molecular analysis showed that the expression levels of a number of ABA and stress marker genes were altered in both AtPUB19 overexpressing and atpub19-1 mutant plants.In summary,our data show that AtPUB19 negatively regulates ABA and drought responses in A.thaliana.
