Characterization of an Iron Regulated Glutathione Transporter (IGT) Reveals Novel Links Between Iron Deficiency and Glutathione

Abstract

We have cloned an Fe-deficiency regulated GT (IGT) from rice. IGT localized to plasma membrane when expressed in onion epidermal cells. Expression of IGT is highly upregulated in response to Fe-deficiency as revealed by microarray, northern blot and promoter GUS analysis. IGT transported GSH in Xenopus leavis oocytes confirming that it is a functional GT. Microarray analysis indicated that igt mutant cultured under Fe-sufficient conditions was deficient in shoot Fe, in spite of the presence of high Fe and ferritin in shoot tissue. GSH localized to root tips in WT plants grown under Fe deficient conditions while it did not localized to root tips in igt plants grown under same conditions. The difference in GSH localization between igt and WT roots not only provided second line of support for IGT as GT but also highlighted the role of GSH in Fe-deficiency stress.