Identification Of Differentially Expressed Genes Induced By Salt Stress In Triticum Aestivum L.

Salt stress is one of the environmental stress. Recently cultivated agricultural land haslargely become saline owing to land clearing or irrigation, the consequence ofsaline-alkali land is the significantly reduction in the yield of most crop. It has beendemonstrated that the reduction of crop yield is due to the decrease on plant weight, leafarea, root vigor, relative growth and so on. Currently, crop breeders face with thechallenge of improving salt tolerance and developing salt tolerance cultivars. Wheat isone of the main crops in the world, and it is much meaningfully to study the salt-tolerancemechanism of wheat for the development of agriculture. In this study, we measured thephysiological indices of nineteen wheat materials firstly, and then analysed the fingerprintof transcriptome in six wheat matrials, screened and cloned the salt tolerance genes inwheat-L.multicaulis disomic addition line material.1.The physiological indices under salt treatments can firmly prove the salt tolerance ofdifferent wheat materials. In this study, we measured the germination rate of seeds,electrical conductivity of seedlings, the length of shoots and roots and the fresh and dryweight in these nineteen wheat materials. Six was chosen depending on the results aboveand the relationship among them, and used for the following study.2. The Na+and K+contents in the six wheat materials were measured in the tissue ofshoots and roots under salt treatment. After analyzing, we found that the four salttolerance materials had three different salt tolerance mechanisms, which means that thesix materials selected are the proper wheat materials to study.3. By the technology of cDNA-AFLP, line Line15with wheat-L.multicaulis disomicaddition was screened for salt-induced genes in shoots and roots through multiplecultivars comparisons. Among132transcript-derived fragments (TDFs),78TDFs werealigned in plant database. And15TDFs were previously reported to be associated withvarious abiotic stresses.4. We used quantitative real time PCR (qRT-PCR) to validate the expression pattern ofTDF76(S-adenosylmethionine synthetase SAMS) coming from cDNA-AFLP. Theexpression level of SAMS was greatly improved at24h in all the six wheat materials, butespecially higher in Line15compared with others. All these indicate that the study ofSAMS is important to explore the salt tolerance mechanism of wheat-L.multicaulisdisomic addition line. 5. Bioinformatic analysis and molecular cloning were used to identify and isolate theSAMS genes in Chinese Spring. Through the amplifications of special and conservedprimers, we found that there are six copies in Chinese Spring and located on chromosomeA, B, D genomes of group6. Our work provides valuable information to further explorethe function of SAMS gene in Line15.