A Vacuolar Phytosiderophore Transporter Alters Iron and Zinc Accumulation in Polished Rice Grains
Open Access
- 22 July 2019
- journal article
- research article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 181 (1), 276-288
- https://doi.org/10.1104/pp.19.00598
Abstract
Essential metals, such as iron (Fe) and zinc (Zn), in grains are important sources for seed germination and nutritional requirements, but the molecular mechanisms underlying their loading into grains are poorly understood. Recently, nodes in rice (Oryza sativa) were reported to play an important role in the preferential distribution of mineral elements to the grains. In this study, we functionally characterized a rice gene highly expressed in nodes, OsVMT (VACUOLAR MUGINEIC ACID TRANSPORTER), belonging to a major facilitator superfamily. OsVMT is highly expressed in the parenchyma cell bridges of node I, where Fe and Zn are highly deposited. The expression of OsVMT was induced by Fe deficiency in the roots but not in the shoot basal region and uppermost node. OsVMT localized to the tonoplast and showed efflux transport activity for 2′-deoxymugineic acid (DMA). At the vegetative stage, knockout of OsVMT resulted in decreased DMA but increased ferric Fe in the root cell sap. As a result, the concentration of DMA in the xylem sap increased but that of ferric Fe decreased in the xylem sap in the mutants. In the polished rice grain, the mutants accumulated 1.8- to 2.1-fold, 1.5- to 1.6-fold, and 1.4- to 1.5-fold higher Fe, Zn, and DMA, respectively, than the wild type. Taken together, our results indicate that OsVMT is involved in sequestering DMA into the vacuoles and that knockout of this gene enhances the accumulation of Fe and Zn in polished rice grains through DMA-increased solubilization of Fe and Zn deposited in the node.Keywords
Funding Information
- Japan Society for the Promotion of Science (16H06296)
This publication has 61 references indexed in Scilit:
- Preferential Delivery of Zinc to Developing Tissues in Rice Is Mediated by P-Type Heavy Metal ATPase OsHMA2Plant Physiology, 2013
- Iron biofortification in rice by the introduction of multiple genes involved in iron nutritionScientific Reports, 2012
- Role of the node in controlling traffic of cadmium, zinc, and manganese in riceJournal of Experimental Botany, 2012
- Phytosiderophore Efflux Transporters Are Crucial for Iron Acquisition in Graminaceous PlantsJournal of Biological Chemistry, 2011
- Plasma membrane-localized transporter for aluminum in riceProceedings of the National Academy of Sciences of the United States of America, 2010
- Gene limiting cadmium accumulation in riceProceedings of the National Academy of Sciences of the United States of America, 2010
- A Highly Sensitive, Quick and Simple Quantification Method for Nicotianamine and 2′-Deoxymugineic Acid from Minimum Samples Using LC/ESI-TOF-MS Achieves Functional Analysis of These Components in PlantsPlant and Cell Physiology, 2009
- Disruption of OsYSL15 Leads to Iron Inefficiency in Rice PlantsPlant Physiology, 2009
- Deoxymugineic acid increases Zn translocation in Zn-deficient rice plantsPlant Molecular Biology, 2008
- A Novel Major Facilitator Superfamily Protein at the Tonoplast Influences Zinc Tolerance and Accumulation in ArabidopsisPlant Physiology, 2007