The Role of ZIP family members in iron transport

Abstract

Deficiencies of micronutrients such as iron negatively impact plant and human health. Thus, understanding the uptake of iron from the soil is clearly the first step towards engineering plants better able to grow in soils now considered marginal, to increase crop biomass on soils now in cultivation and to improve the iron content of plant-based foods. IRT1 is the major iron transporter induced in the roots during the iron deficiency response. It is a founding member of the ZIP family of metal transporters, which includes over 100 proteins found in many diverse organisms including bacteria, fungi, mammals and plants. Here we review the role of IRT1 and other ZIP family members in iron transport in a variety of plant species including tomato, rice, Medicago truncatula and the hyperaccumulator Thlaspi caerulescens. Using IRT1 as the example, we then review how iron controls gene expression, transcriptionally through iron regulated transcription factors such as FER and FIT1 and posttranscriptionally, probably via protein turnover. Ultimately, we hope to understand iron transport at the whole plant level; progress on determining how plants sense and respond to iron is also presented. © 2006 Springer.