Abstract
Iron is an essencial micronutrient for all the organisms. Iron is incorporated into heme and iron-sulfur cluster, thus works as a cofactor of apoproteins. Previous studies have suggested that biogenesis and transport of mitochondrial iron-sulfur cluster play an important role in whole-cell iron metabolism. To gain a new insight into iron availability in plants, we performed a functional analysis of rice Isu (Iron-sulfur cluster assembly U), OsIsu1. Expressed in yeast cells, OsIsu1 functionally complemented yeast endogenous Isu to maintain mitochondrial iron homeostasis. OsIsu1:GFP localized in mitochondria in onion epidermal cells, like Isu of other species. In Arabidopsis transformed with OsIsu1 promoter:GUS, GUS activity was detected in a vascular bundle and young leaves, which could be active sights of iron transport. Heterologous expression of OsIsu1 in Arabidopsis improved growth under the iron starvation. These results suggest the importance of mitochondrial iron-sulfur cluster biosynthesis on whole-plant iron availability.
