Construction of cDNA Library from Populus euphratica

In order to isolate and clone salt-tolerance involved genes of Populus euphratica, we constructed a cDNA library from salt-treated leaves of P. euphratica. In the experiment, double strand cDNA were synthesized by a beads-based method. The syntheses of the first strand and the second strand cDNA, adapter ligation and restriction reaction for releasing cDNA were all conducted on the beads. The double strand cDNA were released from magnetic beads by digestion with NotI, and cDNA fragments smaller than 500 bp and residual adapters were removed through cDNA size fractionation columns. Finally, double strand cDNA were directionally cloned into λExcell vector. The results show that the primary titer of the cDNA library is 7.46×10⁶ pfu per mL and the packaging efficiency reaches 1.47×10⁷ recombinants per μg DNA. λDNA extracted from two clones of plaque were digested by EcoR I and NotI, both of the clones contained inserts larger than 900 bp. These results show that the cDNA library of salt-treated P. euphratica leaves has been successfully constructed.