MTP1-dependent Zn sequestration into shoot vacuoles suggests dual roles in Zn tolerance and accumulation in Zn-hyperaccumulating plants

Jeffery L. Gustin, Marcello E. Loureiro, Donggiun Kim, Gunnam Na, Marina Tikhonova, David E. Salt

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The integral membrane protein Thlaspi goesingense metal tolerance protein 1 (TgMTP1) has been suggested to play an important role in Zn hyperaccumulation in T. goesingense. Here, we show that the TgMTP1 protein is accumulated to high levels at the vacuolar membrane in shoot tissue of T. goesingense. TgMTP1 is likely to act in the transport of Zn into the vacuole, enhancing both Zn accumulation and tolerance. By specifically expressing TgMTP1 in Arabidopsis thaliana shoots, we show that TgMTP1, localized at the vacuolar membrane, can drive the enhanced shoot accumulation of Zn by initiating a systemic Zn deficiency response. The systematic response includes increased expression of Zn transporters (ZIP3, ZIP4, ZIP5 and ZIP9) in both shoot and root tissue. Furthermore, shoot-specific accumulation of TgMTP1 at the vacuolar membrane also leads to increased resistance to Zn in A. thaliana, probably through enhanced Zn compartmentalization in the vacuole. Such evidence leads to the conclusion that the high levels of TgMTP1 at the vacuolar membrane in shoot tissue of the Zn hyperaccumulator T. goesingense play a role in both Zn tolerance and enhanced Zn uptake and accumulation, via the activation of a systemic Zn deficiency response.

Original languageEnglish
Pages (from-to)1116-1127
Number of pages12
JournalThe Plant Journal
Issue number6
Publication statusPublished - Mar 2009


  • MTP
  • Thlaspi
  • hyperaccumulation
  • Zn deficiency
  • grafting
  • micronutrient
  • quantitative trait loci
  • zinc-transporter genes
  • thlaspi-caerulescens
  • arabidopsis-thaliana
  • metal homeostasis
  • plasma-membrane
  • cellular compartmentation
  • Halleri
  • cadmium
  • expression

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