J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (10): 2349-2367.DOI: 10.1111/jipb.13552

• Molecular Physiology • Previous Articles     Next Articles

The aquaporin MePIP2;7 improves MeMGT9-mediated Mg2+ acquisition in cassava

Qiuxiang Ma1*, Yancai Feng1,2, Shu Luo1,2, Lu Cheng1,2, Weijing Tong1,2, Xinlu Lu1, Youzhi Li3* and Peng Zhang1,2*   

  1. 1. National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai 200032, China;
    2. College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    3. State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/College of Life Science and Technology, Guangxi University, Nanning 530004, China
    *Correspondences: Qiuxiang Ma (qxma@cemps.ac.cn); Youzhi Li (dyzl@gxu.edu.cn); Peng Zhang (zhangpeng@cemps.ac.cn, Dr. Zhang is fully responsible for the distribution of all materials associated with the article)
  • Received:2023-02-20 Accepted:2023-08-03 Online:2023-08-07 Published:2023-10-01

Abstract: Aquaporins are important transmembrane water transport proteins which transport water and several neutral molecules. However, how aquaporins are involved in the synergistic transport of Mg2+ and water remains poorly understood. Here, we found that the cassava aquaporin MePIP2;7 was involved in Mg2+ transport through interaction with MeMGT9, a lower affinity magnesium transporter protein. Knockdown of MePIP2;7 in cassava led to magnesium deficiency in basal mature leaves with chlorosis and necrotic spots on their edges and starch over-accumulation. Mg2+ content was significantly decreased in leaves and roots of MePIP2;7-RNA interference (PIP-Ri) plants grown in both field and Mg2+-free hydroponic solution. Xenopus oocyte injection analysis verified that MePIP2;7 possessed the ability to transport water only and MeMGT9 was responsible for Mg2+ efflux. More importantly, MePIP2;7 improved the transportability of Mg2+ via MeMGT9 as verified using the CM66 mutant complementation assay and Xenopus oocytes expressing system. Yeast two-hybrid, bimolecular fluorescence complementation, co-localization, and co-immunoprecipitation assays demonstrated the direct protein–protein interaction between MePIP2;7 and MeMGT9 in vivo. Mg2+ flux was significantly elevated in MePIP2;7-overexpressing lines in hydroponic solution through non-invasive micro-test technique analysis. Under Mg2+-free condition, the retarded growth of PIP-Ri transgenic plants could be recovered with Mg2+ supplementation. Taken together, our results demonstrated the synergistic effect of the MePIP2;7 and MeMGT9 interaction in regulating water and Mg2+ absorption and transport in cassava.

Key words: aquaporin, cassava, magnesium transporter, nutrient utilization, protein interaction

Editorial Office, Journal of Integrative Plant Biology, Institute of Botany, CAS
No. 20 Nanxincun, Xiangshan, Beijing 100093, China
Tel: +86 10 6283 6133 Fax: +86 10 8259 2636 E-mail: jipb@ibcas.ac.cn
Copyright © 2022 by the Institute of Botany, the Chinese Academy of Sciences
Online ISSN: 1744-7909 Print ISSN: 1672-9072 CN: 11-5067/Q