Construction and Analysis of Subtractive cDNA Library of Phellodendron amurense under Drought Stress

With cDNA from Phellodendron amurense seedlings treated under drought stress as tester and the same cDNA under normal growth conditions as driver, we constructed subtractive cDNA library using suppression subtractive hybridization (SSH). In the library, the rate of recombination was 95%, the size of inserts was in the range of 300-800 bp. Two hundred and sixty-five new genes were obtained by the DNA sequencing of 816 positive clones picked randomly, and partitioned to 16 classes after nucleotide blast and blastX homological analysis against NT, NR, SWISSPROT, and KEGG database. Forty-four drought stress associated genes such as heat shock protein cognate 70, dehydration responsive protein 22, universal stress protein, metallothionein II, and late embryogenesis abundant protein were obtained. These genes included osmotic regulator, signal component regulatory protein, and antioxidant enzyme. This research established a basis for cloning stress resistance genes and further studying the genes expression in P. amurense seedlings under drought stress.