Salicylic Acid Induced Self-excision of the Marker Gene npt Ⅱ Using CreloxP System from Transgenic Tobacco

Transgenic plants, despite a great deal of scientifi c evidences, have induced a number of environmental and consumer concerns for long time because various antibiotic resistance genes, according to common

Transgenic plants, despite a great deal of scientific evidences, have induced a number of environmental and consumer concerns for long time because various antibiotic resistance genes, according to common transformation strategies, will accompany engineered crops at all times. Several approaches, which have proven feasible, have been developed to excise marker genes from transgenic plants. The Cre-loxP site-specific recombination system from bacteriophage P1, which express the Cre protein to result in recombination between loxP sites, is one of the strategies mostly eliminated selectable marker in transgenic plants （Chen et al., 2003; Chen et al., 2004）. Either the transient expression or an inducible factor to turn on the expression of cre gene is existed in current Cre-loxP excision system. It requires crossing with a recombinase-expressing line and does not optimize to be functional for clonally propagated crops. Therefore, the strategies of self-excision of selectable markers mediated by CreloxP recombination system are coming to front （Cuellar et al., 2006; Mlynarova and Nap, 2003; Yuan et al., 2004; Zhang et al., 2006）.