Establishment Of Immature Embryo Transgenic System And Transformation Of DWF4 Gene By Agrobecterium Tumefaciens In Maize Inbred-lines

Maize is important feed, industrial material and grain crops and significant for the country's economic and social development. Genetic improvement of maize is a good way of biological technology research and innovation maize varieties. Maize inbred lines of Qi319, Chang7-2 and 178 were used as experimental material, studying systematicallythe establishment of efficient young embryo transgenic system and influence factors. Mediated-by Agrobecterium, BR biosynthesis enzymes DWF4 were transferred to maize, We obtained transgenic plants of Qi319. The conclusion were as follows:1. The result showed that immature embryos of 1.6 mm in length, sctutellum side up, 10¹5 days after-pollinated,and cultured at 24²5℃would grow more embryogenic callus when establishing the accepter system. The combination of 2,4-D(3.0 mg L^-1) and NAA(0.2 mg L^-1) supplemented with induction medium could increase embryogenic callus formation. The callus inductivity of Qi319, Chang7-2,178 would be up to100%, 85%, 35% respectively. Normal callus were pre-screened by culturing on medium with different concentration of paromomycin(PRM), the concentration were 80 mg L^-1,120 mg L^-1 and 80 mg L^-1 for Qi319, 90, 120 and 90 mg L^-1 for 18-599, whereas 55 mg L^-1, 100 mg L^-1 and 55 mg L^-1 for Chang7-2 respectively.2. The process of infection was controlled easily when OD600 of aquicultural agrobecterium was 0.4 and inoculated time(10 min), co-cultivation with filter paper can effectively control Agrobecterium growth and decrease the infectivity.3. PCR detection of the 31 putative transplants preliminaryly confirmed that 3 positive plants were obtained, the rate of positive plants were up to 12.9%, the percent of transformation was 0.26%.