Development of the organized technology for increasing productivity of iron-added crop plants in calcarerous soi

1.获得了T2代转基因水稻种子。这些水稻在石灰性土壤上耐缺铁。利用烟草密码子的用法，通过聚合酶链式反应合成了与酿酒酵母fre1基因氨基酸序列(ORF)相同的fre1基因。该基因被导入烟草并在体内表达，表现出对石灰性土壤缺铁的耐受性。为了获得更耐受的品种，我们采用体外进化的方法合成了refre1：1基因。该基因产物在高pH(pH 8~9)条件下具有比fre1基因更高的酶活性。将refre1基因导入烟草，获得了耐碱性土壤的烟草菌株。研制了含有FeCl2或Fe3+-EDTA的聚烯烃包膜肥料，并对其在几种蔬菜、水稻田和旱地水稻上的应用方法进行了综述。结果表明：如果植物根系不与包膜肥料直接接触或附着，肥料释放到土壤中的铁立即被固定，而不被植物根系吸收。碱性土壤中较稳定的铁源可能是麦芽酸-Fe3+。用于商业用途的芥子酸的大规模生产正在等待着。

1. The transgenic rice seeds of T2 generation were obtained. These rice are tolerant to iron-deficiency in calcareous soils.2. The fre1 gene which had the same amino acid sequence (ORF) as Fre1 gene of Saccharomyces cerevisiae was synthesized by PCR using the codon-usage of tobacco. The gene was introduced into tobacco and was expressed in a whole body, showing tolerance to iron deficiency in calcareous soil. To get more tolerant cultivar, we synthesyzed refre1 : 1 gene by in vitro evolution method. This gene products had higher enzymatic activity at high pH (pH8-9) than fre1 gene. The refre1 gene was introduced into tobacco and tobacco strains tolerant to alkaline soils than refre1-tobacco was obtained.3. Polyolefine-coated fertilizers which include FeCl2 or Fe3+-EDTA were developed, and the application methods of these fertilizers to several vegetables, lowland rice and upland rice were surveyed. The results were concluded as follows : If plants roots were not attached or contacted directly to the coated fertilizers, the released iron from the fertilizer into the soil was immediately immobilized, and was not absorbed by the plant roots. The more stable iron source in the alkaline soil may be mugineic acid-Fe3+. Mass production of mugineic acid for commercial use is awaited.