Iron Uptake in Arabidopsis thaliana

铁是所有高等植物必需的营养物质，含铁化合物在光合作用和呼吸作用的电子传递系统中占有重要地位。虽然铁在土壤中是丰富的，但铁的获取是有问题的，因为铁在好氧条件下在生物pH下的溶解度很低。利用生物化学、遗传和分子遗传技术，研究拟南芥模式植物系统的铁摄取机制。重点是发生在根表面的铁的还原，因为铁的还原可能是使铁可供植物吸收的主要因素。主要目的是鉴定编码铁还原酶活性所需成分的基因。鉴定这些基因的三种策略将同时进行：a)利用酵母中的FRE1基因鉴定拟南芥同源基因；b)对fre1-1酵母突变体进行互补，鉴定拟南芥同源基因；c)鉴定铁还原酶活性改变的拟南芥突变体，并利用这些突变体克隆涉及铁还原的基因。对拟南芥铁吸收的研究应应用于一般的跨膜渗透过程及其调控，并可能最终导致铁高效植物品种的构建。这些研究也有助于揭示根特异性基因表达和金属对基因表达的调控。* * *

9318093 Guerinot Iron is an essential nutrient for all higher plants, with iron- containing compounds figuring prominently in the electron transport systems of photosynthesis and respiration. Although iron is abundant in the soil, the acquisition of iron is problematic due to its low solubility at biological pH under aerobic conditions. Iron uptake mechanisms are being studied in the model plant system, Arabidopsis thaliana, using biochemical, genetic and molecular genetic techniques. The focus is on the reduction of ferric iron which takes place at the root surface because ferric reduction is probably the primary factor in making iron available for absorption by plants. The main objective is to identify genes which encode components necessary for ferric reductase activity. Three strategies to identify such genes will be pursued simultaneously: a) use of the FRE1 gene from yeast to identify an Arabidopsis homolog; b) complementation of the fre1-1 yeast mutant to identify an Arabidopsis homolog; and c) identification of Arabidopsis mutants with altered ferric reductase activity and use of such mutants to clone the gene(s) involved in ferric reduction. A study of iron uptake in Arabidopsis should have application to general transmembrance permeation processes and their regulation and may ultimately lead to the construction of iron efficient plant varieties. These studies should also shed light on root specific gene expression and the regulation of gene expression by metals. ***