转基因水稻胚乳中表达铁结合蛋白提高稻米铁含量

为提高我国稻米的铁含量，通过农杆菌介导将自行克隆的菜豆(Phaseolus limensis)铁结合蛋白(Ferritin)基因导入了一个高产粳稻(Oryaz sativa L.ssp．japonuica)品种中，获得17个独立的转基因水稻株系。分子检测证明，外源基因在多数转基因水稻植株基因组中有1～3个整合位点，并可稳定遗传。在水稻种子贮存蛋白谷蛋白基因GluB-1启动子的控制下，铁结合蛋白基因可在转基因水稻的种子中高效特异地表达，不同转化子中的表达量有明显不同。在转基因水稻种子中表达铁结合蛋白后对提高精米中的铁含量有明显的效果，相对于未转化对照最多可提高64％，而锌的含量并无明显变化。

Endosperm-specific Expression of the Ferritin Gene in Transgenic Rice (Oryza sativa L.) Results in Increased Iron Content of Milling Rice

Iron deficiency is the most widespread micronutrient deficiency world-wild,and is estimated to affect about 30% of the world population.To increase the iron content of rice in Chinese,the 764 bp cDNA of ferritin gene was cloned from soybean (Phaseolus limensis),and constructed between the 1 353 bp rice glutelin GluB-1 promoter and NOS terminator in a binary vector pCAMIBA1301.The constructed pYF1067 vector was introduced into Agrobacterium strain EHA105,and used for transformation of the primary callus derived from immature embryos of a high-yielding rice (Oryza sativa L.ssp.japonica) variety Wuxiangjin 9.Under the selection on hygromycin-containing medium,seventeen independent transgenic rice lines,total more than 80 transgenic plants,were finally regenerated,and most of these transgenic rice plants grew normally.PCR and Southern blot analysis of total DNA from primary transformants confirmed that one to three copies of the transgenes integrated into the genome of most of the transgenic plants,and they could be stably transmitted into the progeny of the transgenic rice.Northern blot analysis showed that the ferritin gene could specifically express in the endosperm of transgenic rice with high level,while no or low expression in leaves.The expression level varied among different independent transgenic rice plants.There was a significant effect of the high-expression of ferritin on the increased iron content in transgenic rice,the iron content in the milling rice of transgenic rice was up to 64% higher than that of the untransformed wild-type plant,whereas no significant alteration of the zinc level occurred between these two type rice plants.