The Transformation And Expression Of A Salt-tolerant Gene ScNHX1 Via Agrobacterium Tumefaciens In Soybean

Saline-alkali soil is a major constraint to food production. Now, approximately one-third of the world's cultivated land is unsuitable for crop growth because of high levels of salt. Saline-alkali soil not only decreases the productivity of cultivated land, but also seriously restricts its sustainable use, which directly affects the sustainable development of agriculture. As an oil and economic crop, soybean (Glycine max) plays an important role in the food industry and agricultural production. Although traditional breeding methods may produce the successful salt-tolerant soybean varieties, it has great flaws, such as time-consuming ventures, and genetic instability. With the development of genetic engineering, using genetic engineering technology can develop many soybean types and seeds. Transgenic technology that can overcome the disadvantages of the traditional breeding has great foreground as a new technology in soybean breeding. Cultured salt-tolerant soybean will supply an important way to utilize and improve saline-alkali soil. The aim of the research is to get the resistant soybean seeds through the clone and construction of salt-tolerant gene and transformation of soybean, also to produce a way with economic and ecological benefits to improve saline-alkali soil.With the development of molecular biology, people have cloned many genes that have a great ability to enhance the plants of salt tolerance. As a member of Na~+/H~+ antiporter, the aim gene NHX1 plays an important role in the plants of salt tolerance. In higher plants, the tonoplast Na~+/H~+ antiporter NHX1 can obviously improve salt tolerance by the transportion of Na~+ from cytoplasm into vacuole. In this study, the ScNHX1 was cloned from Suaeda corniculata that was a salt-tolerant plant in the northeast China and the gene sequences were almost the same with those from GenBank containing the necessary function parts, and then recombinant salt-inductive expression vector pBIGFPScNHX1 was constructed.A soybean species named Jilin 35, the main soybean cutivars in Jilin province, was used in this study. The ScNHX1 was transferred and expression into soybean mediated by Agrobacterium tumefaciens LBA4404. Using the embryonic tips transformation, 144 explants were infected and 42 resistant shooters were obtained through antibiotic screening. Finally, we got 23 plants by grafting. PCR assay showed that 7 plants were positive and transformation efficiency rate reached up to 16.7%.Our research results showed that the embryonic tips transformation system had higher regeneration frequency, short regeneration cycle, and easier to get resistant plants compared with other methods. Especially for solving the rooting difficulty by grafting, it will become the first choice of soybean transformation.