Molecular regulation mechanism of iron uptake in strategy I plants

摘要

Tomato and Arabidopsis are two model plants for studying molecular mechanism of iron uptake in strategy I plants.Several genes involved in iron homeostasis were isolated and characterized in the two plants. Tomato FER and its homolog AtbHLH29 in Ara- bidopsis, encoding a bHLH protein, are a central transcription factor regulating the iron deficiency responses and iron uptake in roots of tomato and Arabidopsis because the insertion mutants of FER (T3238fer) in tomato and AtbHLH29 (fit l-1) in Arabidopsis lacks such responses and suffers strongly from iron deficiency. CHLN encodes a nicotianamine synthase responsible for synthesis of nicotianamine in higher plants. It is directly or indirectly involved in down-regulation of iron deficiency responses consldenng that nicotiananmine-auxotrophic mutant chloronerva in tomato can not normally shut off the iron deficiency responses under iron sufficiency condition. Using the mutants as well as their wild types in tomato and Arabidopsis, we studied the regulation relaionship among the known genes and a molecular regulation model of iron uptake has been proposed for the strategy I plants.