Chin Bull Bot ›› 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:2016-08-05 Published:2016-07-01
  • Contact: Zhang Junxia
  • About author:

    # Co-first authors


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.

Figure 1

T-DNA insertion pattern of Arabidopsis MGT7 mutants mgt7-1 and mgt7-2 Grey boxes: Exons; black lines: Introns"

Figure 2

Comparison of the root length (A) and leaf fresh weight (B) of Arabidopsis mgt7 mutant and Col-0 under different concentrations of Ca2+ * indicate the significant differences at P<0.05."

Figure 3

Phenotypic analysis (A) and fresh weight comparison (B) of Arabidopsis mgt7 mutants on CK medium containing 1 mmol·L-1 and 10 mmol·L-1 Ca2+, respectively, aftering adding 2 mmol·L-1 different mineral element * indicate the significant differences at P<0.05."

Figure 4

Histochemical staining of Arabidopsis roots with stable expression of pMGT::GUS under different concentrations of Ca2+"

Figure 5

Effects of high Ca2+ on the expression of MGT in leaves (A) and roots (B) of Arabidopsis"

Figure 6

The comparison of Arabidopsis mgt7 mutant total Ca (A) and total Mg (B) under different concentration of Ca2+ Different letters above the columns indicate the significant differences at P<0.05"

Figure 7

The effects of high Ca2+ on the cytoplasmic calcium concentration ([Ca2+]cyt) of Arabidopsis (A) The 10 mmol·L-1 Ca2+-induced transient rise of the [Ca2+]cyt; (B) The comparison of mgt7 mutant’s cytoplasm Ca2+ under different concentration of Ca2+"

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