The Construction Of A Selectable Marker-free Vector In Plant And The Obtaining Of Genetically Modified Soybean

Removal of the selectable marker genes from genetically modified (GM) crops alleviates the risk of its release into the environment and hastens the public acceptance of GM crops. To produce marker-free transgenic soybean, the pX6-GFP vector which is a Cre/loxP-mediated site-specific DNA recombination system was constructed. The constructive promoter G10-90 in pX6-GFP was replaced with a seed-specific promoter of soybean952 (the promoter ofα-subunit ofβ-conglycinin) and then the p952-GFP vector we need was constructed. We obtained the transgenic spires by transforming p952-GFP into the soybeans'cotyledonary node mediated by agrobacterium. Upon induction byβ-estradiol(5μM/L), sequences encoding the selectable marker, Cre, and XVE sandwiched by two loxP sites were excised from the soybean genome, leading to activation of the downstream GFP (green fluorescent protein) reporter gene.