Okayama University Discovers Magnesium Transporter Affecting Rice Seed Development and Eating Quality!

June 16, 2026
Okayama University, National University Corporation

https://www.okayama-u.ac.jp/

＜Key Points of the Announcement＞

The transporter protein OsMGR2 discovered in this study is a magnesium efflux transporter that moves magnesium from inside the cell to the outside.

OsMGR2 is expressed in rice roots, nodes, and caryopses, playing a vital role in the translocation of magnesium from roots to shoots and its distribution within nodes and seeds. When this gene is disrupted, seeds become lighter and eating quality deteriorates.

◆ Overview

A research group led by Professor Jian Feng Ma of the Institute of Plant Science and Resources at Okayama University (Headquarters: Kita-ku, Okayama City; President: Yasutomo Nasu), part of the Advanced Science Research Center, collaborated with research groups including Professor Takao Miyaji from the University’s Graduate School of Medicine, Dentistry and Pharmaceutical Sciences and Dr. Kiyosumi Hori from the National Agriculture and Food Research Organization (NARO), to discover the magnesium transporter OsMGR2, which affects rice seed development and eating quality.

These research results were published on April 22, 2026, in the journal "Proceedings of the National Academy of Sciences" issued by the U.S. National Academy of Sciences.

Magnesium is an essential nutrient for both animals and plants. However, how minerals in soil are transported to seeds and the impact of magnesium on seed development and quality have long remained unclear. This study revealed that OsMGR2 is expressed in rice roots, nodes, and caryopses, functioning to efficiently transport magnesium to seeds.

This research is expected to contribute to the development of magnesium deficiency-tolerant rice varieties and high-magnesium accumulating rice cultivars in the future.

This announcement was made public on May 23, 2026.

Figure. Growth of osmgr2 mutant under different magnesium concentrations

◆ Comment from Professor Jian Feng Ma

This research was initiated when Dr. Sheng Huang, currently at Hunan Agricultural University in China, was affiliated with the Plant Stress Biology Group at Okayama University’s Institute of Plant Science and Resources. It took over five years to complete. This was an original study linking magnesium transporters to rice yield and quality, receiving very high evaluations from reviewers. His daily dedication led to this achievement.

Professor Jian Feng Ma and Researcher Dr. Sheng Huang (right)

◆ Paper Information
Title: A magnesium efflux transporter required for seed development and eating quality in rice.
Japanese Title: "A Magnesium Efflux Transporter Essential for Rice Seed Development and Eating Quality"
Journal: Proceedings of the National Academy of Sciences of the United States of America
Authors: Sheng Huang, Kiyosumi Hori, Naoki Yamaji, Yuma Yoshioka, Min Ning, Yu Nagaya, Takaaki Miyaji, Namiki Mitani-Ueno, Shin-ichiro Inoue, June-Sik Kim, Miho Kashino, and Jian Feng Ma
DOI: 10.1073/pnas.2536813123
URL: https://www.pnas.org/doi/10.1073/pnas.2536813123

◆ Research Funding
This study was primarily supported by the Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (Grant-in-Aid for Scientific Research (S) JP21H05034; Principal Investigator: Jian Feng Ma).

◆ Detailed Research Content
Discovery of a Magnesium Transporter Affecting Rice Seed Development and Eating Quality!

https://www.okayama-u.ac.jp/up_load_files/press_r8/press20260423-1.pdf

◆ References

・Okayama University Institute of Plant Science and Resources (IPSR)
https://www.rib.okayama-u.ac.jp/
・Okayama University Institute of Plant Science and Resources, Plant Stress Biology Group
http://www.rib.okayama-u.ac.jp/plant.stress/index-j.html

◆ Reference Information 1

・[Okayama University] Discovery of a novel transporter that excretes iron from cells at rice nodes! Aiming to balance iron levels and develop crops resilient to environmental changes

https://prtimes.jp/main/html/rd/p/000003579.000072793.html

・[Okayama University] Structural basis of citrate transporter responsible for aluminum tolerance in barley revealed

https://prtimes.jp/main/html/rd/p/000003289.000072793.html

・[Okayama University] Discovery of a long-distance signaling protein controlling silicon uptake in rice! Expectations for increased silicon accumulation and stress-resistant crops

https://prtimes.jp/main/html/rd/p/000002811.000072793.html

・[Okayama University] World's first discovery of a transporter responsible for accumulating silicon to protect rice from stress! Expectations for stable crop production and improved safety using silicon

https://prtimes.jp/main/html/rd/p/000001753.000072793.html

・[Okayama University] Boron uptake in rice is post-translationally regulated via a clathrin-independent pathway
https://prtimes.jp/main/html/rd/p/000000538.000072793.html

・[Okayama University] Zinc transport in rice: Balancing plant requirements and human nutrition
https://www.rib.okayama-u.ac.jp/researchactivity/20220303-2/

・[Okayama University] Structural elucidation of silicic acid transporter essential for stable high yield in rice
https://prtimes.jp/main/html/rd/p/000000333.000072793.html

・[Okayama University] Identification of transporter Lsi3 involved in loading silicic acid into rice xylem
https://prtimes.jp/main/html/rd/p/000000542.000072793.html

・[Okayama University] Successful development of low-cadmium-accumulating rice without affecting yield and taste by identifying a gene that suppresses cadmium accumulation in rice

https://prtimes.jp/main/html/rd/p/000000836.000072793.html

◆ Reference Information 2

・[Okayama University] Professor Jian Feng Ma and Associate Professor Naoki Yamaji of Okayama University’s Institute of Plant Science and Resources selected for the 2025 edition of "World's Most Influential Scientific Minds"

https://prtimes.jp/main/html/rd/p/000003685.000072793.html

・[Okayama University] Okayama University Advanced Science Research Center, Advanced Research Cluster holds the 2025 "Plant and Light Energy Development Hub" Research Symposium