| Potassium is an essential nutrient for crop production and harvest. However, the problems of potassium deficiency in cultivated soil are more serious. Therefore the potassium deficiency has become a limiting factor to increase the quality and yield of crops. To adapt to such detrimental conditions, plants have developed a broad range of defense strategies to copes with their environmental stresses, requiring abiotic stress-responsive gene to regulate. With the continuous development of genetic engineering technology, a lot of responsive genes at low quantity potassium stress have been found. It is an effective way of the efficient utilization of potassium in soil to study the function of low potassium tolerance gene and apply them to agricultural production. Under the condition of low-potassium, plant absorb potassium in soil mainly through the high affinity of potassium transporter. It is particularly important that functions of these genes was studied. The paper carried out the research of transgenic Zm HAK1 arabidopsis and the construction of RNAi expression vector, aiming to explore the ability of transgenic Arabidopsis thaliana with Zm HAK1 gene to absorb and transport K+.The p Cambia1301-Zm HAK1 was transformed into the Arabidopsis thaliana by the dipping method. Basta of 0.1 percentage concentration was used to identify the transformed strains. Zm HAK1 gene was successfully transformed into arabidopsis by the results of PCR. The stable inherited transgenic arabidopsis T5 generation was acquired by breeding, screening and identification.After detecting the gene of Bar and Zm HAK1, q RT-PCR was compiled to determine the expression level of Zm HAK1 in T5 generation plants. The results showed that Zm HAK1 gene was expressed in all tissues of transgenic arabidopsis, and had no specific expression. However, the expression level in roots and stems were higher than the other organ. The Zm HAK1 gene expression levels were analyzed of root, stem, flower from transgenic arabidopsis in low-potassium stress. The results showed that its expression was induced obviously by low potassium stress. Gene expression amount of target gene increased at different degree and maintained a high expression level in different tissues, especially, which reached peak in the roots at 72 h and it’s expression amount reached 19 times than that at 0h.The results of potassium uptake kinetics indicated Imax value was higher and Km, Cmin, β values were lower and absorption equilibrium reached in a relatively little time in transgenic line than that in the mutants. Those indicated that the ability of uptake potassium was strong and utilization efficiency was good. The amount of uptake potassium and potassium utilization index were higher in transgenic line than that in the mutants. So, transgenic line not only had a strong ability of uptake potassium but also had a better utilization efficiency. The results of physiological indices at the stress demonstrated that the damage degree of cells in transgenic line was lower than that in the mutants. Furthermore, the resistant ability to the low amount potassium was high and response at the stress was gotten in transgenic line.Compared the roots, flowering time and maturity traits of transgenic arabidopsis with that of mutant under low amount potassium, the results showed that florescence time of transgenic plants was earlier and thousand-grain weight was heavier. Under low amount potassium, the roots of transgenic plants were significantly longer than that of the mutant in a certain range, which indicated that transgenic plants had the better adaptability to the stress of low amount potassium.The plant RNAi expression vector p RNAi-Zm HAK1 was constructed for the convenience of genetic transformation of maize. It was expected that Zm HAK1 gene expression in maize was interfered by RNAi technology in order to further explore its function. |
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