Environmental stresses,such as drought,negatively affect plant growth and production.A number of bZIP transcription factors involved in ABA signaling have been identified through characterization of the ABRE binding factors(ABFs),including ABF1,ABF2,ABF3 and ABF4.ABF2/AREB1,ABF3,and ABF4/AREB2 have been reported to play key roles in the response to drought stress.Mutations in the genes encoding the catalytic subunits of a Ser/Thr PROTEIN PHOSPHATASE(named as PP60),cause a drought tolerance phenotype in Arabidopsis thaliana.Protein-protein interaction assay showed that PP60 interacts with ABF2/3/4 in planta.So we put forward a hypothesis that PP60 may regulate ABFs to improve the tolerance of drought.Gene expression analysis and other molecular characterization of the candidate targets of PP60 will be presented.