Regulation of Iron-deficincy Tolerance in Plants

1. 在过去的二十年里，我们已经克隆了所有的氨基酸合成基因。其中Ids2（缺铁特异性克隆）；2)用于分析ORF上游区域的缺铁调节元件（IDEs）。将缺失的2kb Ids2启动子序列与gus基因融合，将其引入烟草中，分析了缺铁条件下转基因烟草的gus活性。鉴定出两种顺式元素是诱导缺铁的必要成分。通过将3个碱基突变序列依次导入到集中的40个碱基中，确定了IDE1的最小序列为19个碱基，制作了转基因烟草，并分析了缺铁条件下各转基因植株的GUS活性。另一个IDE2的最小序列正在进行中。将“Hvnas1-HvnaatA”基因引入水稻中，筛选出具有较高耐钙质土壤潜力的T2种子。这些转基因水稻正在准备进行田间试验，以获得政府的许可。通过位点诱变对酵母铁还原酶（Fre1）基因进行修饰，合成了refrel基因，并将其引入水稻中。T1植株目前正在钙质土壤盆栽试验中进行筛选。

1. We have cloned all genes on the mugineic acid synthesis in the past two decades. Among them Ids2 (Iron deficiency specific clone no.2) was used for the analysis of iron-deficiency regulatory elements (IDEs) in the upstream region of the ORF. Deletion series of 2 kb Ids2 promoter were fused with gus gene, those genes were introduced into tobacco and GUS activity were analyzed under Fe deficiency in those transgenic tobacco. Two cis elements were identified as necessary parts for induction by Fe deficiency. Minimum sequence of IDE1 was determined as 19 bases by sequential introduction of 3 base mutation into the focused 40 bases, making transgenic tobacco and GUS activity was analyzed for each transgenic plants under Fe deficiency. The minimum sequence of the other IDE2 is under the way.2. We introduced 'Hvnas1-HvnaatA' genes into rice, T2 seeds which had high potential to be tolerant in calcareous soils were selected. Those transgenic rice are now under preparation for field experiment for the governmental permittion.3. We synthesized refrel gene by modification of yeast Fre1 (ferric reductase ) gene by site-directed mutagenesis, and introduced the refre1 genes into rice. T1 plant is now under screening in the pot experiments in calcareous soils.