| Rainless region and semiarid region account for one third of the earth land surface area. In these areas, lack of water has been a bottleneck that restricts the development of agriculture and forestry, has a strong impact on the living and development of human. Illustrating the drought-resistant mechanism of the plants grown in these areas will be beneficial to improving the production potential of these areas. With this aim, a suppression subtractive hybridization library of Tamarix albiflonum was constructed using the osmosis treated leaves, and the expression pattern of osmotic related gene was analyzed. Furthermore, the drought related gene was cloned from the library, and the osmotic resistant mechanism was exploited. This establish basis for the further application in plant drought-resistant breeding.Two hundred and seven effective sequences which obtained from Two hundred and eighty eight randomly picked positive colonies were accepted by the GenBank under accession numbers from EB187088 to EB187295. BlastX alignment results revealed that 79 fragments showed significant similarity to the function-known sequences in NCBI database, and 19 fragments were similar to function-unknown genes. All the sequences in this library were subjected to GO annotation for understanding their roles in molecular function, biological process, and cell component. According to their physiological function, they can be subdivided into 10 categories, among them, 52 genes were osmotic stress-related genes, and their function including signal transduction and gene expression regulation, osmotic substances synthesis, defense, transport facilitation and ions balancing, active oxygen elimination, cell rescue, defensive protein synthesis, photosynthesis repair and protection system and many other physiological and biochemical pathway.We get many osmotic resistant related gene fragments including G protein (EB187186, EB187233,EB187126), calreticulin (EB 187218), serine/threonine kinase (EB 187235), calcium-binding EF hand family protein (EB 187165), putative calcium-dependent protein kinase (EB 187146), adenylyl cyclase associated protein (EB 187222), MAP3Ka (EB187182), trehalose-6-phosphate synthase (EB187156), dehydrin DHN6(EB187153), alpha-mannosidase glycosyl hydrolase family 38 (EB 187148), lipid transfer protein (EB 187132), plasma membrane MIP protein (EB 187092), catalase (EB 187294), elFl (EB 187220), translation initiation factor-like protein (EB 187205), putative transcription elongation factor (EB 187159), putative leucine zipper protein (EB 187102), zinc finger protein (EB187252), and many other crucial genetic information.In this paper the gene encoding the T. albiflonum Aquaporin (AQP) was amplified by 5'rapid amplification of cDNA end (RACE) based on the sequence information (EB187092) obtained from the suppression subtractive hybridization library. The cDNA of the T. albiflonum AQP gene is 1043 bp long, named as TaAQP, and deposited in GenBank with the accession number DQ660891, encoding a protein of 287 amino acids with a predicted molecular mass of 30.9KDa, including 70bp 5'-UTR and 109bp 3'-UTR, has 6 transmembrane regions, and possessing the MIP family signal consensus sequence HINPAVTFG and the higher plant PIP highly conservative sequence GGGANXXXXGY and TGI/TNPARSL/FGAAI/VI/VF/VN. A comparative molecular analysis of nucleotide sequence in NCBI databases showed that it share 95% homology with the gene of Arabidopsis thaliana(MlP-C), with a theoretical isoelectric point of 8.84. And further analysis showed that its instability coefficient is 36.67, indicated it was a stable protein, and its mean hydrophilicity is 0.377, complying with the general properties of transport protein.Tamarix albiflonum is a unique species in Xinjiang, there has been no report about the construction of SSH library up to now. The cloning and characterization of aquaporin gene in this species is the first time. |
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