Localization of Iron in <i>Arabidopsis</i> Seed Requires the Vacuolar Membrane Transporter VIT1

TLDR

Iron deficiency is a major human nutritional problem wherever plant‑based diets are common. Synchrotron x‑ray fluorescence microtomography was used to directly visualize iron in Arabidopsis seeds, revealing localization primarily to the provascular strands of the embryo. Loss of VIT1 abolishes iron localization to the embryo’s provascular strands, and VIT1 disruption impairs seedling growth under iron limitation, highlighting the transporter’s essential role in seed iron storage and its potential to improve seed nutritional quality.

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.