The Tentative Establishment Of A New Foreign Gene Elimination System In Rice Endosperm

The twin T-DNA co-transformation method and Cre/LoxP system have nowbecome two efficient and commonly used methods to breed SM-free transgenic rice.In this study, we reform the connection type of the two T-DNA on the twin T-DNAco-transformation vector,as the reform of LB-RB—LB-RB to RB-LB—LB-RB, for itcould insert into the rice genome as a linked-integration in a large probability. What'smore, the Cre/LoxP system was construct into the twin T-DNA co-transformationsystemin this study,expecting to establish a new method to fixed-point deleteexogenous genes in transgenic rice.We have used the twin T-DNA co-transformation vector which is reformed ornot to construct four plant expression vector, and each one carried the Cre/LoxPsystem(with the Gluc and Gt1tissue specific promoter).In the four plant expressionvector, the Hyg is as the selectable marker gene and gus as the target gene. Trough theAgro-bacterium mediated transformation; we got the transgenic rice and made asystem of molecular test to the effect. The result shows that the un-linked-integrationprobability of the two T-DNA in the reformed twin T-DNA co-transformation systemhas increased, that is55.81%and51.28%, respectively. While the previous ones are47.37%å'Œ45.83%. And all the unlinked-integration of the T-DNA in theco-transformation plant have insolate in the T1gnenration.What's more, the Cre/LoxPsystem mediated by twin T-DNA co-transformation could inherit stably and induce thesite specific deletion of exogenous gene in endosperm of transgenic rice. So thoughthe study we established a new method to fixed-point delete exogenous genes intransgenic rice.