Application of the genes of Fe metabolism in plants to food, environment and human health

摘要

①In order to produce tolerant rice cultivars to low Fe-availability in calcareous soils, we developed several traits containing various types of genes relating to mugineic acid synthesis. Those are now allowed to assay tolerance to calcareous soil in the restricted field for genetically engineered crops. ②Synthetic refrel gene was again mutated by PCR under 0.05 mM MnSO_4, the cDNA were introduced into yeast, and we got a new variant (refre1-1) having 30 times higher ferric reductase activity than refrel at pH 9.0. ③For phytoremediation transgenic HvNAS-Arabidopsis and HvNAS-tobacco were developed by transformation. Both plants showed tolerance to heavy metal toxicity, especially to Ni. ④We developed Fe-fertilizer which is very effective to supply Fe~(2+) as the sole source of Fe. The concentration of the solubilized Fe~(2+)was kept constant more than one year in water. This fertilizer will be very useful for the growth of rice in paddy field of calcareous soils. ⑤In order to generate hypotensive rice, HvNAS was introduced into rice with OsGluterin-promoter. This transgenic rice seeds contained 2-5 times more NA than wild-type. ⑥To get more tolerant cultivars to calcareous soil of low Fe-availability, we are now undergoing to cloning the genes of trans-factor(s) which can conjugate with IDE1 and/or IDE2.