[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.