Localization of Iron in Arabidopsis Seed Requires the Vacuolar Membrane Transporter VIT1

Abstract

Iron deficiency is a major human nutritional problem wherever plant-based diets are common. Using synchrotron x-ray fluorescence microtomography to directly visualize iron in Arabidopsis seeds, we show that iron is localized primarily to the provascular strands of the embryo. This localization is completely abolished when the vacuolar iron uptake transporter VIT1 is disrupted. Vacuolar iron storage is also critical for seedling development because vit1-1 seedlings grow poorly when iron is limiting. We have uncovered a fundamental aspect of seed biology that will ultimately aid the development of nutrient-rich seed, benefiting both human health and agricultural productivity.

Iron Deficiency-Induced Secretion of Phenolics Facilitates the Reutilization of Root Apoplastic Iron in Red Clover

“…Redistribution of nutrients is an important strategy for plants to maintain some semblance of normal growth under nutrient-deficient conditions. Most recently, a vacuolar Fe uptake transporter (VIT1) was demonstrated to play a critical role in Fe localization into the vacuolar and the provascular strands of the embryo; elimination of VIT1 function inhibited reutilization of seed Fe storage during the germination (Kim et al, 2006). In wheat, an ancestral wild allele encoding a NAC transcription factor (NAM-B1) accelerated senescence and increased nutrient remobilization, while loss of function resulted in a significant decrease of wheat grain protein, Zn, and Fe (Uauy et al, 2006).…”

Analysis of engineered nanomaterials in complex matrices (environment and biota): General considerations and conceptual case studies

“…Ideally, sample preparation can involve a range of options including the mounting of whole organisms [51] or cryogenic sectioning of tissues [52]. Elementspecific X-ray microtomography techniques are also available for localization of trace elements in small samples without the requirement for sectioning [53]. Detection limits are generally in the low microgram-per-gram range for detection and in the low to mid microgram-per-gram range for spectroscopic measurements.…”

Transition metal transport

“…It is hypothesized that an IREG1-like protein has been maintained in C. merolae as an adaptation to its environment, where an iron efflux function might be important to cope with high iron availability of the acidic sulphur-rich hot springs [21]. Similar to the situation for IREG proteins, a homologue of the S. cerevisiae CCC1 protein, which transports iron into the vacuole, is encoded in the genomes of A. thaliana (AtVIT1) [41], rice and C. merolae, but not in the C. reinhardtii genome.…”