Regulating Subcellular Metal Homeostasis: The Key to Crop Improvement

Abstract

Iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) are essential micronutrient mineral elements for living organisms, as they regulate essential cellular processes, such as chlorophyll synthesis and photosynthesis (Fe, Cu, and Mn), respiration (Fe and Cu), and transcription (Zn). The storage and distribution of these minerals in various cellular organelles is strictly regulated to ensure optimal metabolic rates. Alteration of the balance in uptake, distribution, and/or storage of these minerals severely impairs cellular metabolism and significantly affects plant growth and development. Thus, any change in the metal profile of a cellular compartment significantly affects metabolism. Different subcellular compartments are suggested to be linked through complex retrograde signaling networks to regulate cellular metal homeostasis. Various genes regulating cellular and subcellular metal distribution have been identified and characterized. Understanding the role of these transporters is extremely important to elaborate the signaling between various subcellular compartments. Moreover, modulation of the proteins involved in cellular metal homeostasis may help in the regulation of metabolism, adaptability to a diverse range of environmental conditions, and biofortification. Here, we review progress in the understanding of different subcellular metal transport components in plants and discuss the prospects of regulating cellular metabolism and strategies to develop biofortified crop plants.

Contrasting cadmium resistance strategies in two metallicolous populations of Arabidopsis halleri

“…One strategy is efficient Cd chelation followed by vacuolar sequestration (e.g. via phytochelatin binding) or by direct transport into the vacuole, which can be mediated by HMA3 and Cation Exchanger (CAX) 2 and 4 (Bashir et al ., ). Another strategy proposed for both A. thaliana and A. halleri is the activation of antioxidant mechanisms or the prevention of ROS accumulation by CAX1‐mediated cytosolic calcium (Ca) sequestration in vacuoles to avoid the Ca–ROS positive feedback loop (Baliardini et al ., , ).…”

Genome-wide Association Studies of Agronomic Traits Consisting of Field- and Molecular-based Phenotypes

“…It is known that there is cross-talk in mineral uptake and accumulation among the ions, such as between Zn-Fe and As-P (Pineau et al, 2012;LeBlanc et al, 2013). Especially in transport system, molecular mechanism of Cu, Fe, and Zn homeostasis and their interactions, which often include interactions with toxic metals, were releveled in plants (Puig et al, 2007;Bernal et al, 2012;Sinclair and Krämer, 2012;Bashir et al, 2016). These reports suggested that integration of multiple GWAS results targeting various minerals could identify the loci controlling the cross-talk of uptake and accumulation of multiple minerals.…”

Analytical Methods for Imaging Metals in Biology: From Transition Metal Metabolism to Transition Metal Signaling

“…2–7 Moreover, too much or too little of a given metal nutrient in a given location can be detrimental to the living system. 8–11 …”