Abstract: The total RNA was extracted from Populus euphratica under salt stress with the 600mmol·L^-1 NaCl treatment, and then the cDNA library was constructed by SMART technique, which uses λTriplEx2 as a vector. The estimated titer and the percentage for the unamplified salt stress library (SSL) is 1.2×10⁶ pfu·ml^-1 and 90.6%. Selected cDNA clones randomly and the EST were obtained by 3′ sequenced, these sequences were compared in GenBank databases. 32 Expressed Sequence Taqs (ESTs) were gained from the SSL with high homologous sequences, 71.8% are assigned putative identities. The sequences from the remaining clones showed either significant similarity to protein or DNA sequences that were of unknown function or no significant similarity to any other sequences in the databases. Two of the SSL transcripts encoding dehydrin may be connected with salt stress. Meanwhile, two primers of nhx were synthesized and the full length nhx cDNA of Populus euphratica was successfully obtained from this library to identify the high quality library using PCR.

Key words: Populus euphratica, salt stress, cDNA library, nhx