Iron in Plants

Abstract

Iron (Fe) is a universal nutritional requirement for virtually all organisms, functional as an electron carrier in respiration and photosynthesis, in the production and detoxification of oxygen radicals, oxygen transport and numerous reduction and monooxygenase reactions. Depending on the redox potential of the environment, Fe occurs in two stable oxidation states, Fe 3+ and Fe 2+ that differ dramatically in their solubility in water. Plants have evolved two distinct, phylogenetically separate mechanisms driven by an increasing abundance of photosynthesis‐derived atmospheric oxygen, which makes Fe unavailable due to the formation of highly insoluble ferric oxides. Excess Fe is toxic to cells. Therefore, cellular Fe concentrations are tightly regulated by sophisticated mechanisms that control acquisition, distribution and utilisation of Fe. A large proportion of the world's arable land has soil properties that do not allow the uptake of sufficient Fe for optimal plant growth and yield, making an understanding of the mechanisms that control cellular homoeostasis mandatory for the development of Fe‐efficient germplasms. Key Concepts: With only few exceptions Fe is a universal nutritional requirement by all organisms. Iron occurs in two stable oxidation states, Fe 3+ and Fe 2+ , that differ dramatically in their solubility in water. A large proportion of the world's arable land has soil properties that do not allow the uptake of sufficient Fe for optimal plant growth and yield. Plants have evolved two distinct, phylogenetically separated mechanisms for Fe uptake. The evolution of Fe uptake mechanisms is likely driven by the increasing concentration of photosynthesis‐derived atmospheric oxygen. Cellular Fe concentrations are tightly regulated by sophisticated mechanisms that control acquisition, distribution and utilisation of Fe. The primary sensor for Fe deficiency has yet to be identified.

Molecular Analysis of Iron Deficiency Response in Hexaploid Wheat

“…In plants, iron functions as redox-active metal in many important reactions of metabolic processes such as photosynthesis, mitochondrial respiration, nitrogen assimilation, hormone biosynthesis, and the production and scavenging of reactive oxygen species (Hansch and Mendel, 2009). Although iron ranks as the fourth most abundant element in the earth's crust (Buckhout and Schmidt, 2013), plants often suffer from iron deficiency due to the low bioavailability of iron in aerobic, calcareous and/or high pH soils (Morrissey and Guerinot, 2009). Iron deficiency causes interveinal chlorosis because of insufficient chlorophyll production that is often identified as alternate yellow and green stripes in younger leaves of most cereals (Barker and Stratton, 2015).…”

“…Some NATURAL RESISTANCE ASSOCIATED MACROPHAGE PROTEIN (NRAMP) such as AtNRAMP3 and AtNRAMP4 function in transporting iron out of vacuoles, whereas VACUOLAR IRON TRANSPORTER (VIT) has the opposite function (Lanquar et al, 2005;Zhang et al, 2012). Most of the iron in plants is found in leaf chloroplasts (Buckhout and Schmidt, 2013). PERMEASE IN CHLOROPLASTS 1 (PIC1) is associated with iron transport across the inner chloroplast envelope in Arabidopsis and tobacco (Duy et al, 2007(Duy et al, , 2011Gong et al, 2015), and Arabidopsis AtYSL4 and AtYSL6 export iron out of chloroplasts (Divol et al, 2013).…”

Archives of Environmental Protection

“…Iron is an indispensable element for the normal growth and development of plants, primarily because of its role in metabolic processes (Thomine and Lanquar 2011). It functions as an electron carrier in respiration and photosynthesis, participates in the production and detoxification of oxygen radicals, as well as in the course of many chemical reactions (Buckhout and Schmidt 2010). The Fe content in broad bean leaves in our experiment ranged from 109.17 to 150.84 mg kg -1 of dry mass.…”

System analysis of differentially expressed miRNAs in hexaploid wheat display tissue-specific regulatory role during Fe deficiency response

“…[1]. Despite being the fourth most abundant element in the earth's crust, its bioavailability to plants is restricted owing to its presence as sparingly soluble Fe 3+ form in aerobic and high pH soil environment [2,3]. Fe deficiency in plants causes interveinal chlorosis and drastically impacts vegetative growth and crop yield [4].…”