| Salinization of soil is one of the major abiotic-stress that influence agricutural production and environment.Global salinization of soil run up to ten hundreds million hectare,and there are about a hundred million hectare of salt lick.Salinization is getting worse because of secondary salt injury.The identification of salinity tolerance of wheat has important significance not only for the study of genetic improvement of crops,but also the cultivation of wheat that introduced as an important component.The experiment identified the salinity tolerance at germination stages of wheat that were introduced from the United States,selected some wheat germplasms that have higher salinity tolerance at germination stages.At the same time,the research cloned a heat shock protein gene hsp20 that was induced through Na Cl treatment.On the basis of bioinformatics analysis,identified the function of the gene by analyzing of gene expression and transgenic Arabidopsis.The main research results are as follows:1.The salinity tolerance at germination stages of wheat that were introduced from the United States.The experiment identified the salinity tolerance at germination stages more than 400 wheat germplasms which was introduced from the United States,screened the high salt tolerant wheat varieties that the salt injury index below 20%,and screened 35 types of salt tolerant wheat that the salt stress index under 40%.At the same time,we have statistics of the germinating wheat that in the 2% Na Cl treatment,we found that the higher the germination rate is,the lower the salt damage index would be,in other words the relationship between them is negatively correlated.2.The bioinformatics analysis of heat shock protein geneThe bioinformatics analysis results showed that the gene contains a conservative functional domain of the heat shock protein gene,we used the NCBI web site found that the heat shock protein gene contains an ORF 477 bp,which encodes 158 amino acids and encodes a protein without a trans-membrane domain and no signal peptide.The amino acids are acidic amino acids,its optimum absorption peak at 280 nm and its electricity point is 5.6 by Ex PAsy Prot Paramtool tool.Further,we analyzed the two stage structure and three stage structure of heat shock protein.The data show that the protein was mainly composed of alpha helices(10.8%),irregular coils(25.9%)and beta folds(55.1%).Among them,alpha helix is the main one.The results showed that the structural features were consistent with the heat shock protein.3.The analyzing of gene expressionThe data of the gene chip hybridization showed that heat shock protein gene was up-regulated,when subjected to salt stress.And it showed the expression difference between the salt sensitive wheat Ji'nan 177 and the salt tolerant wheat SR3.The expression analysis showed that the salt tolerance SR3 root of wheat than Ji'nan in 177 by using the RT-PCR method.The gene was up-regulated at 0.5h under Salt Stress in Wheat leaves.4.The identified the function of the geneWe obtained transgenic homozygous gene Arabidopsis thaliana by screening Arabidopsis seedlings.Then the transgenic Arabidopsis seedlings' s anti Na Cl ability was identified,and the results showed that the transgenic plant have longer root length than wild plants in 50mmol/L and 100mmol/LNa Cl in MS medium;Determination of the physiological indexes showed that the transgenic plants accumulated higher proline content than the wild type,confirmed that the wheat heat shock protein gene expression in Arabidopsis can enhance the drought resistance of plants.In the determination of POD enzyme activity,POD enzyme activity of transgenic plants was generally higher than WT.in addition,also measured water loss rate,the data showed that the rate of water loss of Transgenic plant have a lower water loss rate genetically than that of wild type.These results suggest that the overexpression of heat shock protein gene can improve the ability of the transgenic plants to resist salt and drought. |
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