Samuelsen A I, Martin R C, Mok D W, Mok M C
Department of Horticulture and Center for Gene Research and Biotechnology, Oregon State University, Corvallis, Oregon 97331-7304, USA.
Plant Physiol. 1998 Sep;118(1):51-8. doi: 10.1104/pp.118.1.51.
Two yeast genes, FRE1 and FRE2 (encoding Fe(III) reductases) were placed under the control of the cauliflower mosaic virus 35S promoter and introduced into tobacco (Nicotiana tabacum L.) via Agrobacterium tumefaciens-mediated transformation. Homozygous lines containing FRE1, FRE2, or FRE1 plus FRE2 were generated. Northern-blot analyses revealed mRNA of two different sizes in FRE1 lines, whereas all FRE2 lines had mRNA only of the expected length. Fe(III) reduction, chlorophyll contents, and Fe levels were determined in transgenic and control plants under Fe-sufficient and Fe-deficient conditions. In a normal growth environment, the highest root Fe(III) reduction, 4-fold higher than in controls, occurred in the double transformant (FRE1 + FRE2). Elevated Fe(III) reduction was also observed in all FRE2 and some FRE1 lines. The increased Fe(III) reduction occurred along the entire length of the roots and on shoot sections. FRE2 and double transformants were more tolerant to Fe deficiency in hydroponic culture, as shown by higher chlorophyll and Fe concentrations in younger leaves, whereas FRE1 transformants did not differ from the controls. Overall, the beneficial effects of FRE2 were consistent, suggesting that FRE2 may be used to improve Fe efficiency in crop plants.
将两个酵母基因FRE1和FRE2（编码铁（III）还原酶）置于花椰菜花叶病毒35S启动子的控制之下，并通过根癌农杆菌介导的转化导入烟草（Nicotiana tabacum L.）。产生了含有FRE1、FRE2或FRE1加FRE2的纯合株系。Northern杂交分析显示，FRE1株系中有两种不同大小的mRNA，而所有FRE2株系仅具有预期长度的mRNA。在铁充足和铁缺乏条件下，测定了转基因植物和对照植物中的铁（III）还原、叶绿素含量和铁水平。在正常生长环境中，双转化体（FRE1 + FRE2）的根中铁（III）还原最高，比对照高4倍。在所有FRE2和一些FRE1株系中也观察到铁（III）还原升高。铁（III）还原增加发生在根的整个长度和茎段上。FRE2和双转化体在水培中对缺铁更耐受，幼叶中的叶绿素和铁浓度更高表明了这一点，而FRE1转化体与对照没有差异。总体而言，FRE2的有益作用是一致的，表明FRE2可用于提高作物植物的铁效率。
