| Maize is one of well-known and important cultivated crops in the world, it also plays important role in China. With the change of crops distribution, farming systems and climate conditions, corn aphid is becoming one of the most important pest, which has affected the maize yield and quality in some area. Based on genetic engineering, anti-aphid gene EβF cloned from mint was transformed into maize embryogenesis callus; resistant regeneration plants have been got. This research added new content and germplasm to modern maize molecular breeding. Meanwhile, it was significant to the insect-resistant gene engineering in maize.Optimizations of receptor system for maize and aphid resistance gene transformation by particle bombardment were researched in this study, the results showed that: the rates of regeneration for several different pretreatment methods in maize embryogenesis callus were compared with: The results showed that 2,4-D concentrations were lower, the higher the regeneration rate were emergence, when the 2,4-D concentration was 0mg/L, the highest plant regeneration rate was emergence. The results indicated that the method of 0mg/L 2, 4-D concentration and 48h dehydration was the best way; at this point regeneration rate could reach 62.86%; the better way was 48h dehydration; finally, the method of 0mg/L 2, 4-D concentration got the lowest differentiation rate.In this study, the growth and regeneration of maize callus were used to define the appropriate screening concentration of several commonly used agents in the genetic transformation. The results were as follows:(1) Maize callus was sensitive to the G418, even at low concentrations of G418 has seriously inhibited the growth of callus. Considering the rate of regeneration factors, suitable concentration range of G418 in the maize callus selection should be 15-20mg/L, as well, screening concentration of hybrid should be slightly higher than the inbred lines.(2) The growth of maize callus was not sensitive to Kan, but Kan played a role of inhibitor on regeneration. 10mg/L of concentration for two twice could effectively inhibit the plant regeneration.(3) Basta's active ingredient is the PPT. The experiment of basic endurance of callus to PPT was done. The result showed optimal concentration for screening after transformation was 5-7mg/L which could evidently blocked the growth and regeneration of callus.Genetically engineered crops could be dangerous to the environment and human health safety, which topic has become a hot issue in our society. Selecting marker gene deletion from transgenetic plants is one effective means to improve the safety of genetically modified organisms. In this study, EβF gene of resistance to aphid was constructed into plasmid pNCX carrying Cre/loxp recombinant system and NPTII selection marker. In this study, we transformed aphid resistance gene EβF cloned from the mint into maize embryo callus by particle bombardment and two plasmids pBJ40 and pNCX has been used. Two different osmotic treatments has been taken into before bombardment:(1) 0.4mol/L mannitol osmotic treatment (2) the filter paper dried for 2h+0.4mol/L mannitol osmotic treatment. The results showed that method (2) got 2.09 regeneration plants per gun, method (1) got 1 regeneration plants per gun, this result preliminary indicated that method (2) better than method(1). The results showed that optimal biolistic rupture pressure and target distance was 1100psi×9cm. PCR analysis of the resistant calli demonstrated that some calli could amplify target fragment and showed the same size in comparison with the positive check, positive rate was 2.13%. The result of PCR amplification confirmed that EβF gene has been integrated into the genomes of maize.
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