Plant Cell Reports

, Volume 37, Issue 12, pp 1653–1666 | Cite as

Triticum urartu MTP1: its ability to maintain Zn2+ and Co2+ homeostasis and metal selectivity determinants

  • Fan-Hong Wang
  • Kun Qiao
  • Shuang Liang
  • Si-Qi Tian
  • Yan-Bao Tian
  • Hong WangEmail author
  • Tuan-Yao ChaiEmail author
Original Article


Key message

TuMTP1 maintains Zn2+ and Co2+ homeostasis by sequestering excess Zn2+ and Co2+ into vacuoles. The mutations NSEDD/VTVTT in the His-rich loop and I119F in TMD3 of TuMTP1 restrict metal selectivity.


Mineral nutrients, such as zinc (Zn) and cobalt (Co), are essential or beneficial for plants but can be toxic at elevated levels. Metal tolerance proteins (MTPs) are plant members of the cation diffusion facilitator (CDF) transporter family involved in cellular metal homeostasis. However, the determinants of substrate selectivity have not been clarified due to the diversity of MTP1 substrates in various plants. In this study, Triticum urartu MTP1 was characterized. When expressed in yeast, TuMTP1 conferred tolerance to Zn2+ and Co2+ but not Fe2+, Cu2+, Ni2+ or Cd2+ in solid and liquid culture and localized on the vacuolar membrane. Furthermore, TuMTP1-expressing yeast accumulated more Zn2+ and Co2+ when treated. TuMTP1 expression in T. urartu roots was significantly increased under Zn2+ and Co2+ stresses. Determinants of substrate selectivity were then examined through site-directed mutagenesis. The exchange of NSEDD with VTVTT in the His-rich loop of TuMTP1 restricted its metal selectivity to Zn2+, whereas the I119F mutation confined specificity to Co2+. The mutations H74, D78, H268 and D272 (in the Zn2+-binding site) and Leu322 (in the C-terminal Leu-zipper) partially or completely abolished the transport function of TuMTP1. These results show that TuMTP1 might sequester excess cytosolic Zn2+ and Co2+ into yeast vacuoles to maintain Zn2+ and Co2+ homeostasis. The NSEDD/VTVTT and I119F mutations are crucially important for restricting the substrate specificity of TuMTP1, and the Zn2+-binding site and Leu322 are essential for its ion selectivity and transport function. These results can be employed to change metal selectivity for biofortification or phytoremediation applications.


Triticum urartu CDF TuMTP1 Zn2+ Co2+ Metal selectivity 



This work was supported by the National Natural Science Foundation of China (Grant no. C31370281, Grant no. U1632111, Grant no. 61672489), the Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences (Grant no. Y4ZK111B01), and the Chinese Academy of Sciences (Grant No. KJRH2015-001).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

299_2018_2336_MOESM1_ESM.docx (256 kb)
Supplementary material 1 (DOCX 256 KB)
299_2018_2336_MOESM2_ESM.xlsx (11 kb)
Supplementary material 2 (XLSX 10 KB)
299_2018_2336_MOESM3_ESM.xlsx (10 kb)
Supplementary material 3 (XLSX 10 KB)
299_2018_2336_MOESM4_ESM.xlsx (14 kb)
Supplementary material 4 (XLSX 14 KB)


  1. Anuradha K, Agarwal S, Rao YV, Rao KV, Viraktamath BC, Sarla N (2012) Mapping QTLs and candidate genes for iron and zinc concentrations in unpolished rice of Madhukar × Swarna RILs. Gene 508(2):233–240CrossRefGoogle Scholar
  2. Blaudez D, Kohler A, Martin F, Sanders D, Chalot M (2003) Poplar metal tolerance protein 1 confers zinc tolerance and is an oligomeric vacuolar zinc transporter with an essential leucine zipper motif. Plant Cell 15(12):2911CrossRefGoogle Scholar
  3. Bloss T, Clemens S, Nies DH (2002) Characterization of the ZAT1p zinc transporter from Arabidopsis thaliana in microbial model organisms and reconstituted proteoliposomes. Planta 214(5):783–791CrossRefGoogle Scholar
  4. Courbot M, Willems G, Motte P, Arvidsson S, Roosens N, Saumitou-Laprade P, Verbruggen N (2007) A major quantitative trait locus for cadmium tolerance in Arabidopsis halleri colocalizes with HMA4, a gene encoding a heavy metal ATPase. Plant Physiol 144(2):1052–1065CrossRefGoogle Scholar
  5. Das N, Bhattacharya S, Maiti MK (2016) Enhanced cadmium accumulation and tolerance in transgenic tobacco overexpressing rice metal tolerance protein gene OsMTP1 is promising for phytoremediation. Plant Physiol Biochem 105:297–309CrossRefGoogle Scholar
  6. Desbrosses-Fonrouge AG, Voigt K, Schröder A, Arrivault S, Thomine S, Krämer U (2005) Arabidopsis thaliana MTP1 is a Zn transporter in the vacuolar membrane which mediates Zn detoxification and drives leaf Zn accumulation. Febs Lett 579(19):4165–4174CrossRefGoogle Scholar
  7. Dräger DB, Desbrosses-Fonrouge AG, Krach C, Chardonnens AN, Meyer RC, Saumitou-Laprade P, Krämer U (2004) Two genes encoding Arabidopsis halleri MTP1 metal transport proteins co-segregate with zinc tolerance and account for high MTP1 transcript levels. Plant J 39(3):425–439CrossRefGoogle Scholar
  8. Gietz D, St JA, Woods RA, Schiestl RH (1992) Improved method for high efficiency transformation of intact yeast cells. Nucleic Acids Res 20(6):1425CrossRefGoogle Scholar
  9. Grotz N, Guerinot ML (2006) Molecular aspects of Cu, Fe and Zn homeostasis in plants. Biochem Biophys Acta 1763(7):595–608CrossRefGoogle Scholar
  10. Johnsonbeebout SE, Goloran JB, Rubianes FH, Jacob JD, Castillo OB (2016) Zn uptake behavior of rice genotypes and its implication on grain Zn biofortification. Sci Rep 6:38301CrossRefGoogle Scholar
  11. Kawachi M, Kobae Y, Mimura T, Maeshima M (2008) Deletion of a histidine-rich hoop of AtMTP1, a vacuolar Zn2+/H+ Antiporter of Arabidopsis thaliana, stimulates the transport activity. J Biol Chem 283(13):8374–8383CrossRefGoogle Scholar
  12. Kawachi M, Kobae Y, Kogawa S, Mimura T, Krämer U, Maeshima M (2012) Amino acid screening based on structural modeling identifies critical residues for the function, ion selectivity and structure of Arabidopsis MTP1. Febs J 279(13):2339–2356CrossRefGoogle Scholar
  13. Landschulz WH, Johnson PF, McKnight SL (1988) The leucine zipper: a hypothetical structure common to a new class of dna binding proteins. Science 240(4860):1759–1764CrossRefGoogle Scholar
  14. Lang M, Hao M, Fan Q, Wei W, Mo S, Zhao W, Jie Z (2011) Functional characterization of BjCET3 and BjCET4, two new cation-efflux transporters from Brassica juncea L. J Exp Bot 62(13):4467CrossRefGoogle Scholar
  15. Liu H, Zhao H, Wu L, Liu A, Zhao FJ, Xu W (2017) Heavy metal ATPase 3 (HMA3) confers cadmium hypertolerance on the cadmium/zinc hyperaccumulator Sedum plumbizincicola. New Phytol 215:687–698CrossRefGoogle Scholar
  16. Lu M, Fu D (2007) Structure of the Zinc Transporter YiiP. Science 317(5845):1746–1748CrossRefGoogle Scholar
  17. Lu M, Jin C, Fu D (2009) Structural Basis for Auto-regulation of the Zinc Transporter YiiP. Nat Struct Mol Biol 16(10):1063CrossRefGoogle Scholar
  18. Marschner H (1995) Mineral nutrition of higher plants. J Ecol 76(4):1250Google Scholar
  19. Martinoia E, Maeshima M, Neuhaus HE (2007) Vacuolar transporters and their essential role in plant metabolism. J Exp Botany 58(1):83–102CrossRefGoogle Scholar
  20. Menguer PK, Farthing E, Peaston KA, Ricachenevsky FK, Fett JP, Williams LE (2013) Functional analysis of the rice vacuolar zinc transporter OsMTP1. J Exp Botany 64(10):2871CrossRefGoogle Scholar
  21. Menguer PK, Vincent T, Miller AJ, Brown JKM, Vincze E, Borg S, Holm PB, Sanders D, Podar D (2018) Improving zinc accumulation in cereal endosperm using HvMTP1, a transition metal transporter. Plant Biotechnol J 16(1):63–71CrossRefGoogle Scholar
  22. Migocka M, Papierniak A, Maciaszczykdziubińska E et al (2014) Cucumber metal transport protein MTP8 confers increased tolerance to manganese when expressed in yeast and Arabidopsis thaliana. J Exp Bot 65(18):5367–5384CrossRefGoogle Scholar
  23. Migocka M, Kosieradzka A, Papierniak A et al (2015a) Two metal-tolerance proteins, MTP1 and MTP4, are involved in Zn homeostasis and Cd sequestration in cucumber cells. J Exp Bot 66(3):1001–1005CrossRefGoogle Scholar
  24. Migocka M, Papierniak A, Anna, Kosieradzka et al (2015b) Cucumber metal transport protein CsMTP9 is a plasma membrane H+ -coupled antiporter involved in the Mn2+ and Cd2+ efflux from root cells. Plant J Cell Mol Biol 84(6):1045–1058CrossRefGoogle Scholar
  25. Montanini B, Blaudez D, Jeandroz S, Sanders D, Chalot M (2007) Phylogenetic and functional analysis of the Cation Diffusion Facilitator (CDF) family: improved signature and prediction of substrate specificity. BMC Genom 8(1):107CrossRefGoogle Scholar
  26. Nakandalage N, Nicolas M, Norton RM, Hirotsu N, Milham PJ, Seneweera S (2016) Improving rice zinc biofortification success rates through genetic and crop management approaches in a changing environment. Front Plant Sci 7(148):764PubMedPubMedCentralGoogle Scholar
  27. Påhlsson AMB (1989) Toxicity of heavy metals (Zn, Cu, Cd, Pb) to vascular plants. Water Air Soil Pollut 47(3–4):287–319CrossRefGoogle Scholar
  28. Palmgren MG, Clemens S, Williams LE, Krämer U, Borg S, Schjørring JK, Sanders D (2008) Zinc biofortification of cereals: problems and solutions. Trends Plant Sci 13(9):464–473CrossRefGoogle Scholar
  29. Paolacci AR, Tanzarella OA, Porceddu E, Ciaffi M (2009) Identification and validation of reference genes for quantitative RT-PCR normalization in wheat. BMC Mol Biol 10:11CrossRefGoogle Scholar
  30. Paulsen IT, Saier JM (1997) A novel family of ubiquitous heavy metal ion transport proteins. J Membr Biol 156(2):99–103CrossRefGoogle Scholar
  31. Persans MW, Nieman K, Salt DE (2001) Functional activity and role of cation-efflux family members in Ni hyperaccumulation in Thlaspi goesingense. Proc Natl Acad Sci USA 98(17):9995–10000CrossRefGoogle Scholar
  32. Pilon-Smits EA, Quinn CF, Tapken W, Malagoli M, Schiavon M (2009) Physiological functions of beneficial elements. Curr Opin Plant Biol 12(3):267–274CrossRefGoogle Scholar
  33. Podar D, Sanders D (2010) Biofortification of barley grains by cell-type-specific expression of a vacuolar metal transporter. Roman Biotechnol Lett 15(2):117–119Google Scholar
  34. Podar D, Scherer J, Noordally Z, Herzyk P, Nies D, Sanders D (2012) Metal selectivity determinants in a family of transition metal transporters. J Biol Chem 287(5):3185–3196CrossRefGoogle Scholar
  35. Ricachenevsky FK, Menguer PK, Sperotto RA, Williams LE, Fett JP (2013) Roles of plant metal tolerance proteins (MTP) in metal storage and potential use in biofortification strategies. Front Plant Sci 4(7):144PubMedPubMedCentralGoogle Scholar
  36. Shingu Y, Kudo T, Ohsato S, Kimura M, Ono Y, Yamaguchi I, Hamamoto H (2005) Characterization of genes encoding metal tolerance proteins isolated from Nicotiana glauca and Nicotiana tabacum. Biochem Biophys Res Commun 331(2):675–680CrossRefGoogle Scholar
  37. Simmerman HK, Kobayashi YM, Autry JM, Jones LR (1996) A leucine zipper stabilizes the pentameric membrane domain of phospholamban and forms a coiled-coil pore structure. J Biol Chem 271(10):5941CrossRefGoogle Scholar
  38. Vida TA, Emr SD (1995) A new vital stain for visualizing vacuolar membrane dynamics and endocytosis in yeast. J Cell Biol 128(5):779–792CrossRefGoogle Scholar
  39. Xu J, Chai T, Zhang Y, Lang M, Han L (2009) The cation-efflux transporter BjCET2 mediates zinc and cadmium accumulation in Brassica juncea L. leaves. Plant Cell Rep 28(8):1235–1242CrossRefGoogle Scholar
  40. Yan J, Wang P, Wang P, Yang M, Lian X, Tang Z, Huang CF, Salt DE, Zhao FJ (2016) A loss-of-function allele of OsHMA3 associated with high cadmium accumulation in shoots and grain of Japonica rice cultivars. Plant Cell Environment 39(9):1941–1954CrossRefGoogle Scholar
  41. Yuan L, Yang S, Liu B, Zhang M, Wu K (2012) Molecular characterization of a rice metal tolerance protein, OsMTP1. Plant Cell Rep 31(1):67–79CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.College of Life SciencesUniversity of Chinese Academy of SciencesBeijingChina
  2. 2.Shenzhen Key Laboratory of Marine Bioresource and Eco-environmental Science, Guangdong Engineering Research Center for Marine Algal Biotechnology, College of Life Science and OceanographyShenzhen UniversityShenzhenChina
  3. 3.Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijingChina
  4. 4.The Innovative Academy of Seed DesignChinese Academy of ScienceBeijingChina
  5. 5.Southeast Asia Biodiversity Research InstituteChinese Academy of SciencesNay Pyi TawMyanmar

Personalised recommendations