Arabidopsis MEB3 functions as a vacuolar metal transporter to regulate iron accumulation in roots

Iron is an essential nutrient for plant photosynthesis and development, but excess iron leads to stress. After absorption from the soil, plants store iron in roots and distribute it to shoots via long-distance transport. The vacuole is involved in iron storage and the maintenance of cellular iron ho...

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Main Authors: Kaichiro Endo, Arpan Kumar Basak, Alwine Wilkens, Mohamadreza Mirzaei, Stanislav Kopriva, Kenji Yamada
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-03-01
Series:Frontiers in Plant Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fpls.2025.1517144/full
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author Kaichiro Endo
Arpan Kumar Basak
Arpan Kumar Basak
Alwine Wilkens
Alwine Wilkens
Mohamadreza Mirzaei
Mohamadreza Mirzaei
Stanislav Kopriva
Kenji Yamada
author_facet Kaichiro Endo
Arpan Kumar Basak
Arpan Kumar Basak
Alwine Wilkens
Alwine Wilkens
Mohamadreza Mirzaei
Mohamadreza Mirzaei
Stanislav Kopriva
Kenji Yamada
author_sort Kaichiro Endo
collection DOAJ
description Iron is an essential nutrient for plant photosynthesis and development, but excess iron leads to stress. After absorption from the soil, plants store iron in roots and distribute it to shoots via long-distance transport. The vacuole is involved in iron storage and the maintenance of cellular iron homeostasis, and vacuolar iron transporter (VIT) family proteins have been identified as plant vacuolar iron transporters. However, the contribution of vacuolar iron transporters to overall iron homeostasis in plants is not fully understood. Here, we show that MEMBRANE PROTEIN OF ER BODY 3 (MEB3), a VIT family member, functions as a vacuolar metal transporter for iron distribution in Arabidopsis thaliana. Heterologous expression of Arabidopsis MEB3 in yeast vacuolar iron or zinc transporter mutants restored the iron- and zinc-resistance phenotypes of the respective mutants, indicating that MEB3 regulates iron and zinc transport. In Arabidopsis, MEB3 was expressed in almost all tissues, albeit to higher levels in roots and seedlings, and MEB3 protein localized to the tonoplast. Iron but not zinc levels were reduced in meb3 knockout mutant roots, suggesting that the knockout reduced iron storage capacity in roots. At high iron concentration, meb3 mutants accumulated more iron in shoots and less iron in roots than the wild type, indicating impairment of proper iron distribution in meb3 mutants. These findings demonstrate that MEB3 is a vacuolar transporter involved in the homeostasis of iron and other metals in plants.
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spelling doaj-art-7bcd22155b964d09be19537acf2da6192025-08-20T03:02:06ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2025-03-011610.3389/fpls.2025.15171441517144Arabidopsis MEB3 functions as a vacuolar metal transporter to regulate iron accumulation in rootsKaichiro Endo0Arpan Kumar Basak1Arpan Kumar Basak2Alwine Wilkens3Alwine Wilkens4Mohamadreza Mirzaei5Mohamadreza Mirzaei6Stanislav Kopriva7Kenji Yamada8Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, PolandMalopolska Centre of Biotechnology, Jagiellonian University, Krakow, PolandFaculty of Biology, Jagiellonian University, Krakow, PolandMalopolska Centre of Biotechnology, Jagiellonian University, Krakow, PolandThe Franciszek Gorski Institute of Plant Physiology, Polish Academy of Sciences, Krakow, PolandMalopolska Centre of Biotechnology, Jagiellonian University, Krakow, PolandDoctoral School of Exact and Natural Sciences, Jagiellonian University, Krakow, PolandInstitute for Plant Sciences, Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, GermanyMalopolska Centre of Biotechnology, Jagiellonian University, Krakow, PolandIron is an essential nutrient for plant photosynthesis and development, but excess iron leads to stress. After absorption from the soil, plants store iron in roots and distribute it to shoots via long-distance transport. The vacuole is involved in iron storage and the maintenance of cellular iron homeostasis, and vacuolar iron transporter (VIT) family proteins have been identified as plant vacuolar iron transporters. However, the contribution of vacuolar iron transporters to overall iron homeostasis in plants is not fully understood. Here, we show that MEMBRANE PROTEIN OF ER BODY 3 (MEB3), a VIT family member, functions as a vacuolar metal transporter for iron distribution in Arabidopsis thaliana. Heterologous expression of Arabidopsis MEB3 in yeast vacuolar iron or zinc transporter mutants restored the iron- and zinc-resistance phenotypes of the respective mutants, indicating that MEB3 regulates iron and zinc transport. In Arabidopsis, MEB3 was expressed in almost all tissues, albeit to higher levels in roots and seedlings, and MEB3 protein localized to the tonoplast. Iron but not zinc levels were reduced in meb3 knockout mutant roots, suggesting that the knockout reduced iron storage capacity in roots. At high iron concentration, meb3 mutants accumulated more iron in shoots and less iron in roots than the wild type, indicating impairment of proper iron distribution in meb3 mutants. These findings demonstrate that MEB3 is a vacuolar transporter involved in the homeostasis of iron and other metals in plants.https://www.frontiersin.org/articles/10.3389/fpls.2025.1517144/fullArabidopsistransporterironmetalvacuole
spellingShingle Kaichiro Endo
Arpan Kumar Basak
Arpan Kumar Basak
Alwine Wilkens
Alwine Wilkens
Mohamadreza Mirzaei
Mohamadreza Mirzaei
Stanislav Kopriva
Kenji Yamada
Arabidopsis MEB3 functions as a vacuolar metal transporter to regulate iron accumulation in roots
Frontiers in Plant Science
Arabidopsis
transporter
iron
metal
vacuole
title Arabidopsis MEB3 functions as a vacuolar metal transporter to regulate iron accumulation in roots
title_full Arabidopsis MEB3 functions as a vacuolar metal transporter to regulate iron accumulation in roots
title_fullStr Arabidopsis MEB3 functions as a vacuolar metal transporter to regulate iron accumulation in roots
title_full_unstemmed Arabidopsis MEB3 functions as a vacuolar metal transporter to regulate iron accumulation in roots
title_short Arabidopsis MEB3 functions as a vacuolar metal transporter to regulate iron accumulation in roots
title_sort arabidopsis meb3 functions as a vacuolar metal transporter to regulate iron accumulation in roots
topic Arabidopsis
transporter
iron
metal
vacuole
url https://www.frontiersin.org/articles/10.3389/fpls.2025.1517144/full
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