| Wheat is one of the main crops in our country, a large quantity of water was required for the whole growth period. However the water resources is shortage in our country, in addition, exacerbated by the effects of global warming and other factors,every wheat planting area suffer from different degrees drought each year. Drought has become the main factors restricting the increase of wheat production in China and seriously impacts wheat yields and national food security. Breeding new varieties of drought resistant water-saving wheat and creating new germplasm of drought resistant and water saving wheat through genetic engineering technology is an important mission for wheat production in the future.In this study, genetically modified T4 wheat by DREB4 A and W17 were detected by PCR and the drought resistance were identificated. 5 good performance strains were choiced respectively combining with conventional breeding experience on the basic of molecular detection. some drought resistance releated physiological and biochemical indexes were measured respectively on the basis of molecular detection,such as chlorophyll, photosynthesis rate, transpiration rate, water use efficiency, leaf relative water content, relative conductivity, malondialdehyde content, proline content,soluble protein content, superoxide dismutase and peroxidase activity, in the heading stage, flowering period, grain filling period; at the same time,yield and other agronomic traits were compared and analyzed; In addition, the drought resistance characteristics of seeds of positive strains were analyzed, some drought tolerance transgenic lines were selected. The main results are as follows:1.PCR detection results: the positive rate of Jimai 19 turned DREB4 A was100%,with 24 positive lines from 24 detected lines; the positive rate of Jimai 19 turned W17 was 97.3%,with 36 positive lines from 37 detected strains. The results showed that exogenous gene had been integrated into the chromosome of wheat and have been stablely geneticed.2.The results of drought resistance related physiological and biochemical indexes show that two transgenic materials DREB4 A and W17 behaved similar change trend.The proline content and soluble protein content in transgenic lines showed a gradual upward trend in three stages from heading to flowering and filling stage. and they were always higher than that of the control, meanwhile the increased significantly are higher than that of the control; The content of chlorophyll and the activity of SOD、POD increased firstly and then decreased, transgenic lines is always higher than that of control. In addition, the reduce score also less than the control, the most significant difference appeared in the filling stage; Photosynthetic rate, water use efficiency, leafrelative water content decreased, the transgenic lines were higher than that of the control.With the aggravation of drought stress, and the most significant difference appeared in the grain filling stage; Transpiration rate, relative conductivity and MDA content rising trend of transgenic lines was lower than that of control, also increased less than the control, and the most significant difference appeared in grain filling stage.These results indicated that drought resistance related transcription factor gene DREB4 A and W17 can significantly improve the performance of drought resistance of wheat.3.Agronomic traits investigation results: Compared with the control, average plant height of Jimai 19 turned DREB4 A or Jimai 19 turned W17 were higher more than 2.0% or 2.4%; length of flag leaf were higher than control by 4.0% and 5.0%respectively. width of flag leaf were higher than that of the control by 1.3% and0.99% respectively. Sequently leaf area was also higher than the control. At the same time, the number of ears per mu were higher than the control by 3.0% and 4.1%respectively. Grain number per spike were higher than the control by 4.1% and 4.9%.One thousand grain weight was higher than that of control by 4.5% and 6.2%, the actual yield per mu were higher than the control 6.0% and 8.3% respectively. To sum up, these results indicating that, the transgenic lines possess higher stress resistance than control, and can maintain a higher yield level under the same water stress.4.There are no significant diference between the two transgentic materials and control about drought related indicators under conditions of adequate moisture;However, the germination rate, coleopitile length, embryo root length, radical length of the two transgentic materials were better than those of the control under stress condition of 20% PEG-6000 and the difference between them is significant. The results showed that the DREB4 A and W17 genes could improve the drought resistance of wheat during the germination period.Above all, this study provide some basic materials and methods reference for the development of the theory and method research of gene engineering of wheat breeding, as well as further the molecular mechanism of drought resistance related transcription factor gene. |
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