Chinese Bulletin of Botany ›› 2016, Vol. 51 ›› Issue (4): 496-503.DOI: 10.11983/CBB15207

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Mg2+ Transporter MGT7 Mediates Arabidopsis thaliana Adapting to High Calcium Environment

Chunli Ma1, Mailisi HeShuote2, Zhi Qi1, Jing Wang1, Junxia Zhang1, 3*   

  1. 1College of Life Sciences, Inner Mongolia University, Hohhot 010021, China
    2University of Oregon, Eugene 97401, USA
    3Hohhot Vocational College, Hohhot 010051, China
  • Received:2015-11-20 Accepted:2016-02-14 Online:2016-07-01 Published:2016-08-05
  • Contact: Zhang Junxia
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    # Co-first authors

Abstract:

A high Ca environment has negative effects on plant growth and development, so the adaptation of plants to high Ca2+ level is important to study. We found that the Arabidopsis Mg2+ transporter MGT7 loss-of-function mutants mgt7-1 and mgt7-2 showed a high Ca2+-sensitive phenotype: under high Ca2+ medium, the leaf fresh weight but not root length decreased significantly compared to the wild type Col-0. The high Ca2+ content had no effect on MGT7 promoter activity and the expression of other Mg2+ transporter genes including MGT7. The mgt7 mutant and the wild type did not differ in extracellular Ca2+-induced cytosolic Ca2+ level and Ca and Mg content. However, with both normal and high Ca2+ media, the Mg content was lower in mgt7 than the wild type. High Ca2+ treatment inhibited Mg2+ accumulation in both mgt7 and the wild type. The mutant’s high Ca2+-sensitive phenotype may be due to decreased Mg content. Increasing the Mg content but not N, P, K or S in the medium fully rescued the high Ca2+-sensitive phenotype.