Abstract:

Fe is one of the most important micronutrients in plant growth and development,and iron deficiency in plant leads to leaves yellowing,which in turn affects yield. There are two mechanisms for plant absorption and transport of iron,that is,mechanism I and mechanism II,the corresponding plant called mechanism I plant and mechanism II plant. Dicots and non-graminaceous monocots employ the mechanism I,and graminaceous plants adopt mechanism II. As the key gene in mechanism I plant,gene FRO（ferric reduction oxidase）has been found and studied in a variety of plants,including graminaceous plant rice. In order to understand the function of FRO in maize,functional analysis of ZmFRO2,a ferric reductase gene in maize,was done,including bioinformatics analysis,expression pattern and subcellular localization. The results indicated that ZmFRO2 had the structural basis of iron reductase and had a closer kinship with OsFRO1,MtFRO1,AtFRO6 and AtFRO7. ZmFRO2 was located in the plasma membrane and cytoplasm. ZmFRO2 gene was expressed in large quantities in leaves and the expression of it was first induced and then inhibited by iron deficiency. In addition,transgenic maize plants with over-expression of ZmFRO2 were obtained using the method of agrobacterium-mediated infection. The iron reductase activity and Zn/Fe content determination of them showed that the over-expression of ZmFRO2 increased the iron reductase activity in maize roots and the iron content in the root,leaf and grain all increased at varied degrees. Through these analyses and determinations,the foundation for the further study of gene function verification is laid,and a new functional gene and a new way for improving iron content of maize will be provided.

Key words: iron reductase gene, ZmFRO2, function verification, iron deficiency stress