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BACKGROUND: Rice is the major food resource for nearly half of the global population; however, insect infestation could severelyaffecttheproductionofthisstaplefood.ToimprovericeinsectresistanceandreducethelevelsofBttoxinreleasedinto the environment, theCry1Abgene was conjugated to the ricerbcS promoter to express Bt toxin in specific tissues of transgenic plants. RESULTS: Eight marker-free, T2 lines were separated from the T0 cotransformants. Using RT-PCR, high levels of Cry1Ab expression were detectedin theleaf butnotinthe seed. The Cry1Abproteinlevel rangedfrom1.66 to3.31 µgg −1 in theleaves offourtransgeniclines,butwasbarelydetectableintheirseedsbyELISA.Bioassaysshowedthatthemortalityrateofsilkworm larvae feeding on mulberry leaves dipped in transgenic rice flour and pollen was less than that of the positive control (KMD), and that their average weight was higher than that of KMD, suggesting that the Cry1Ab protein was not expressed in the seed and pollen. CONCLUSION: The transgene conferred a high level of resistance to insects and biosafety to the rice plants, which could be directly used in rice breeding. c � 2012 Society of Chemical Industry |
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