Abstract：To identify the genes controlling water stress response in Malus sieversii Roem. seedlings, suppression subtractive hybridization (SSH) was applied to construct forward and reverse subtractive cDNA libraries from Malus sieversii Roem cv. Xinyuan 1 treated with 20% PEG 6000. After sequencings 1000 clones from two cDNA libraries at random, 268 UniESTs were isolated. Homology search and sequences annotation were completed by Blastx and Blastn NCBI network service. According to MIPS function catalogue, all UniESTs were classified into 16 classifications. They were ascribed to proteins which were taken part in metabolism, transcription, protein biosynthesis and proteolytic, cell fate, cellular communication transduction, energy metabolism and so on.
