Construction Of EST Database From A Osmosis-Treated Tamarix Albif Lonum M.T.Liu. Suppression Subtractive Hybridization Library And Analysis Of Gene Sequences

In order to study the expression and regulation of osmosis-resistance in Tamarix albif lonumM. T. L iu.,a suppression subtractive hybridization (SSH) library was constructed from thetissue of Tamarix albif lonum M. T. L iu treated with PEG6000, and expressed sequence tags(EST) was researched and analysed.The rate of recombination was 95% and the average length of inserted fragments in thelibrary was 500bp, which was testified by PCR analysis. The positive clones of the library wasrandomly picked for sequencing and analysed showed that 290 ESTs were obtained throughBLASTX. 141 high quality ESTs were gained, in which 100 ESTs were homologous to thegenes identified previously by BLAST from the Internet, while the other 41 ESTs matched tounknown protein coding regions.Analyzing the genes related to drought-tolerance indicated that all the 100 ESTs can bedivided into 14 functional categories.Three groups of transcripts were significantly expressed:transcriptional regulators, protein synthesis and signaling conduction that respesented 9.655%,4.482% and 3.44% respectively. These three processes played important action in the process ofdrought-resistance for Tamarix albif lonum M. T. L iu.The genes related to proteinmetabolism,metabolism, stress protein, transmembrane transport and ion homeostasis andphotosynthesis were expressed more abundantly than the others genes, representing3.103%,2.758%, 2.758%, 1.724%, and 1.724%, respectively. These five processes playedimportant action in the osmosis-resistance also.However, osmolyte biosynthesis gene, reactiveoxygen scavengers and cell wall were expressed less, 1.379%, 1.034% and 1.034%,respectively, probably also play important roles in the process of osmosis-resistance.From above, we can conclude that drought-resistance of Tamarix albif lonum M. T. L iu.wasan complex process that involved signaling conduction, transcription regulation, transmembranetransport and ion homeostasis, reactive oxygen scavenging, osmolyte biosynthesis. The SSHlibrary construction and the acquiring of many ESTs related to stess-resistance will make afoundation for thoroughly understanding the mechanism of stress resistance of Tamarix albiflonum M. T. L iu.