| Salinity soil causes deteterous effects and leads to reduction in wheat production. Improving the salt tolerance in wheat is one of the most important objects of wheat breeding programs. It is very important to map OTLs and clone genes related to salt tolerance, which not only lay a foundation for the map based clone, but also may enhance the resistance under salt stress by transformating the salt tolerance related gene into wheat.1. A RIL population derived from a cross between Opata85 and W7984, was used to detect QTLs related to salt tolerance in wheat under salt stress. 114 RILs was used for the determination of salt related traits, QTL analysis was conducted by using the constructed molecular linkage map and software QTL mapper 1.0. On the whole, 69 QTLs were mapped on 18 chromosomes except for 1B, 1D and 7D, of which 22 QTLs were mapped during germination stage, and 47 QTLs were mapped during seedling stage. On comparison between salt tolerance index and physiology index during germination stage and seedling stage, it was found that many traits related to salt tolerance were mapped to the same intervals of chromosome such as xglk683-xcdo460 on the chromosome 3A, xfbbl68-xbcd147 on the chromosome 3B, xckol081-xfbb226 on the chromosome 4DL and xpsr106-xfbb283 on the chromosome 6DL. QTLs located on the interval xckol081-xfbb226 of the chrosome 4DL were related to salt tolerance on germination stage, the QTLs in the interval xpsr106-xfbb283 on the chrosome 6DL related to salt tolerance on seedling stage; then the QTLs in the intervals xglk683-xcdo460 on the chromosome 3AS and xfbbl68-xbcdl47 on the 3BL related to salt tolerance during the seedling stage and germination stage.2. By homologous based cloning, we isolated the cDNA sequence of TaPSCS gene in wheat with 2260 bp in length. The TaP5CS cDNA sequence contained an open reading frame encoding a protein of 717 amino acids. The deduced protein contains ATP-binding domain, NADPH-binding domain, Glu-kinase domain, GSA-dehydrogenase domain and feedback inhibition site. Southern blot analysis showed that the TaP5CS gene had 2 copies and were mapped on the chromosome 3B. Northern blot and semi-quantitive-RT-PCR show that the expression of TaP5CS mRNA reach first peak at 2 hr after salt stress and then got to the second peak at the 12th hour after salt stress, which showed that the expression of TaP5CS gene is induced under salt stress. The wheat TaP5CS were transformated into Arabidopsis by Agrobacterium tumefaciens with floral dip method. Northern blotting analysis revealed that Wheat TaP5CS were expressed in the transgenic plant under control condition, furthermore, the expression of Wheat TaP5CS in the transgenic plant were increased under the ABA, PEG and salt stress. Over-expression TaP5CS in Arabidopsis can not only enhance the root length, proline content under 50 and 100mM NaCl treament, but also increase protein content, chrollophyll content, shoot biomass andplant height. Antisense TaP5CS in Arabidopsis decrease the proline content and the root length. The antisense TaP5CS transgenic plant had shorter siliques and lower fertility and larger seed than that of the wild type plant. The effect of antisense the shorter sequence P5CS-262 was better than the longer sequence P5CS-2151.3. By homologous based cloning, we cloned the TaP5CR gene in wheat, the 1025 bp TaP5CR cDNA contains an open reading frame encoding a protein of 288 amino acids. The 2600bp genomic DNA contained six introns and seven extron.. Southern blot showed that the TaP5CR gene was more than 2 copies. Northern blot showed the TaP5CR gene express in the control condition and was improved slightly under salt stress. The wheat TaP5CR were transformated into Arabidopsis by Agrobacterium tumefaciens with floral dip method . The very strong expression of TaP5CR in the transgenic plant were confirmed by Northern boltting. The stronger expression of TaP5CR in the transgenic plant enhance the root length and root biomass and incease the proline synthesis and stabi...
|
PDF Full Text Request