J Integr Plant Biol ›› 2022, Vol. 64 ›› Issue (1): 166-182.DOI: 10.1111/jipb.13187

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  • 收稿日期:2021-09-29 接受日期:2021-11-10 出版日期:2022-01-01 发布日期:2022-01-25

An Arabidopsis vasculature distributed metal tolerance protein facilitates xylem magnesium diffusion to shoots under high-magnesium environments

Haiman Ge1†, Yuan Wang2†, Jinlin Chen1, Bin Zhang3, Rui Chen1, Wenzhi Lan1*, Sheng Luan4* and Lei Yang1*   

  1. 1 Nanjing University–Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
    2 Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai 201602, China
    3 Chinese Education Ministry's Key Laboratory of Western Resources and Modern Biotechnology, Key Laboratory of Biotechnology Shaanxi Province, College of Life Sciences, Northwest University, Xi'an 710069, China
    4 Department of Plant and Microbial Biology, University of California, Berkeley, California 94702, USA

    † These authors contributed equally to this work.
    * Correspondences: Wenzhi Lan (lanw@nju.edu.cn); Sheng Luan (sluan@berkeley.edu); Lei Yang (leiyang@nju.edu.cn, Dr. Yang is fully responsible for the distributions of all materials associated with this article)
  • Received:2021-09-29 Accepted:2021-11-10 Online:2022-01-01 Published:2022-01-25
The metal tolerance protein family protein MTP10 is critical for magnesium (Mg) homeostasis in Arabidopsis. MTP10 localizes to the plasma membrane of parenchyma cells and facilitates Mg2+ diffusion from the xylem to shoots, thus determining Mg homeostasis in shoot vascular tissues during high-Mg stress.

Abstract: Magnesium (Mg2+) is an essential metal for plant growth; however, its over-accumulation in cells can be cytotoxic. The metal tolerance protein family (MTP) belongs to an ubiquitous family of cation diffusion facilitator (CDF) proteins that export divalent metal cations for metal homeostasis and tolerance in all organisms. We describe here the identification of MTP10 to be critical for xylem Mg homeostasis in Arabidopsis under high Mg2+ conditions. The Arabidopsis plant contains 12 MTP genes, and only knockout of MTP10 decreased the tolerance of high-Mg stress. The functional complementation assays in a Mg2+ -uptake-deficient bacterial strain MM281 confirmed that MTP10 conducted Mg2+ transport. MTP10 is localized to the plasma membrane of parenchyma cells around the xylem. Reciprocal grafting analysis further demonstrated that MTP10 functions in the shoot to determine the shoot growth phenotypes under high Mg2+ conditions. Moreover, compared to the wild type, the mtp10 mutant accumulated more Mg2+ in xylem sap under high-Mg stress. This study reveals that MTP10 facilitates Mg2+ diffusion from the xylem to shoots and thus determines Mg homeostasis in shoot vascular tissues during high-Mg stress.

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