Development Of Selectively Terminable Rice And Using This System To Produce Human Serum Albumin

Plant transgenic technology has been widely utilized for engineering crops for trait improvements and for production of high value proteins such as pharmaceuticals. However, the unintended spreading of commercial transgenic crops by pollination and seed dispersal is a major concern for environmental and food safety. Thus simple and reliable containment strategies for transgenes are highly desirable. Here we report a novel method for creating selectively terminable transgenic rice, which could be selectively killed by bentazon, an herbicide commonly used for rice weed control. In this method, the gene(s) of interest is tagged by a RNA interference cassette suppressing the expression of the bentazon detoxification enzyme CYP81A6. Using a new glyphosate resistant5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene as an example of the genes of interest, we demonstrated that the transgenic rice plants could be positively selected by glyphosate but negatively selected by bentazon, which is exactly opposite to the conventional rice. Field trials of these transgenic rice plants further confirmed that they can be selectively killed at100%by one spray of bentazon at a regular dose used for weed control of conventional rice. Moreover, we found that the terminable transgenic rice created in this study shows no difference in growth, development and yield compared to its non-transgenic control. Therefore, transgenic rice created by this method will be convenient for detection and termination by an already registered agrichemical.Human serum albumin (HSA) is the most widely used clinical serum protein. Currently, commercial HSA is obtained basically from human plasma. We built a binary T-DNA transformation plasmid1300-R450-200i-HSA, which consists of three parts, an expression cassette for HSA, which is under the control of the major rice seed storage protein promoter GTi, a glyphosate resistant EPSPS gene expression cassttee, and the RNAi cassette suppressing the expression of CYP81A6. The plasmid1300-R450-200i-HSA was used foe transforminf rice by Agrobacterium-mediated transformation method using glyphosate as the selection agent. We obtained several events which express HSA at high levels in the rice seed. And they are highly sensitive to bentazon but tolerant to glyphosate.