Two Transgenic Methods To Obtain Genetically Modified Glyphosate-Resistant Soybean

Soybean originates from China, and due to various reasons, the domestic soybean production is comparatively decreasing. An important factor affecting the production of soybean in China is weeds. Above 80% soybean fields were affected by weeds, and 15% of soybean production was decreased due to the weeds' affection in China. With the development of genetic engineering technology, more and more herbicide-resistance genes are explored, solving weeds problem in soybean fields has taken a turn for the better.In this study, the regenerative capacity of Suinong 22, Suiyu 06-8790, Heinong61, Hefeng 25, Hefeng 35 embryonic tips were studied, and the results showed that the shoot induction rate from adventitious buds ranged from 46.64% to 82.85%among the five soybean genotypes. Heinong 61 showed to be the best in the induction among them, while the rate of Suinong 22 adventitious buds were the lowest, which was 46.64%. On the other hand, the number of adventitious buds among different varieties also showed great differences. The highest average number of buds was 1.67 of Suinong 22, followed by Heinong 61 for 1.35, and the average adventitious number of buds of Hefeng 25 was the lowest, which was 0.63.According to the two aspects of embryonic tips adventitious buds and adventitious buds rate, Heinong embryos tips had stronger regeneration ability, so it was more suitable for genetic transformation system of soybean embryonic tips. The optimal tolerance concentration to glyphosate in the process of induction were also studied,the experimental results showed that in the adventitious buds elongation stage, the glyphosate screening pressure of Suinong 22, Hefeng 25 soybean embryonic tips were 7.5 mg·L-1; Hefeng 35, Suiyu 06-8790 were 10.0 mg·L-1; Heinong 61 soybean embryonic tips identified as 15.0 mg·L-1. Using this method for genetic transformation, ultimately, 12 strains of T0 generation PCR positive plants were gained.In this study we dealed with 5000 explants of five soybean varieties with the method of "minimal wound brush". 46,200 seeds of T0 generation plants were planted and sprayed with glyphosate, the survival soybean plants were tested by PCR,102 glyphosate-resistant transgenic soybean plants PCR results showed positive bands. Finally, the T2 generation genetically modified glyphosate-resistant soybean Suinong 22 and wild-type soybeans Suinong 22 were dealt with Roundup in thisstudy, and chlorophy? content, shikimic acid mass fraction, photosynthetic rate were measured after glyphosate treatment, the genetically modified glyphosateresistant Suinong 22 soybeans exhibited a certain resistance to glyphosate in this three relevant physiological indices compared to wild-type Suinong 22 soybeans,suggesting that EPSPS gene had expressed in the soybean plants.