论文部分内容阅读
Iron is an essential element for plant growth and development, and it plays an important role in a variety of cellular activities including cell respiration, chlorophyll biosynthesis, photosynthetic electron transfer, and DNA synthesis.To better understand the mechanism of iron metabolism, identification and functional analysis of important regulators involved in this process is necessary.In our first study,a member of FROs family gene FRO6, which encodes a ferric chelate reductase functioning as metal ionhomeostasis in Arabidopsis, was overexpressed in wild tobacco to test its roles.High-level expression of AtFRO6 in transgenic plants was observed.Ferric reductase activity in leaves of transgenic plants grown under iron sufficient or iron-deficient conditions is 2.13 and 1.26 fold higher than in control plants respectively.The enhanced ferric reductase activity led to increased concentrations of ferrous iron and chlorophyll, and reduced the iron deficiency chlorosis in the transgenic plants.In roots, the concentration of ferrous iron and ferric reductase activity were not significantly different in the transgenic plants compared to the control plants.These results suggest that FRO6 functions as a ferric chelate reductase for iron uptake by leaf cells, and overexpression of AtFRO6 in transgenic plants can reduce iron deficiency chlorosis.In a parallel study, we cloned and characterized a novel NtPIC1 genefrom Nicotiana tabacum, a homologous gene of Arabidopsis chloroplast iron transporter AtPIC1.Through a series of molecular and genetic analyses of NtPIC1 in tobacco, we conclude that NtPIC1 functions in iron transport across the membrane of chloroplasts and cellular metal homeostasis.Together,these studies shed light on mechanism of the iron metabolism in plants.