Zinc uptake and radial transport in roots of Arabidopsis thaliana: a modelling approach to understand accumulation

Claus, Juliane; Bohmann, Ansgar; Chavarría-Krauser, Andrés

doi:10.1093/aob/mcs263

Cited by 54 publications

(36 citation statements)

References 53 publications

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“…Zn uptake into the symplast in the outer root layers and loading into the apoplastic xylem stream are well understood on molecular level (Moreira, Moraes, & dos Reis, ). However, the dynamics of symplastic movement and patterning of the radial transport have thus far only been modeled to elucidate the timescales of these events (Claus et al., ). After xylem loading, the mass flow‐mediated movement of Zn into the shoot inside the xylem is expected to occur within 30 min in Arabidopsis , as previously shown for water (Park et al., ) and Cd in xylem sap (Ueno et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…The slower speed of Zn transport indicates that Zn loading into the xylem by HMA4 is slow and under tight control even in the metal hyperaccumulator A. halleri . Modelling the radial transport of Zn uptake has indeed indicated that HMA concentration is one of the key determinants of the uptake dynamics (Claus et al., ).…”

Section: Discussionmentioning

confidence: 99%

“…This cell wall‐adsorbed 65 Zn would be desorbed into the growth medium during the imaging period by diffusion. The influx of Zn into the root symplasm is very tightly and rapidly regulated in Zn‐concentration dependent fashion (Claus et al., ; van de Mortel et al., ; Talke et al., ). Without the loading of Zn into the xylem, Zn builds up in the root symplasm.…”

Section: Discussionmentioning

confidence: 99%

“…Within the root, mathematical modeling approaches have explored the importance of ZIP regulation, HMA abundance and symplastic transport in the creation of the radial pattern of Zn within primary roots of A. thaliana (Claus, Bohmann, & Chavarría‐Krauser, ). Modeling predicted that Zn transport in the symplasm takes place at the same time scale as symplastic transport with Zn carried along the water flow path at the same velocity of water (Claus et al., ). Transpiration is thus a key determinant of the rate of this water transport for symplastic, root cell‐to‐cell transport.…”

Section: Introductionmentioning

confidence: 99%

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Real‐time whole‐plant dynamics of heavy metal transport inArabidopsis halleriandArabidopsis thalianaby gamma‐ray imaging

et al. 2019

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Heavy metals such as zinc are essential for plant growth, but toxic at high concentrations. Despite our knowledge of the molecular mechanisms of heavy metal uptake by plants, experimentally addressing the real‐time whole‐plant dynamics of heavy metal uptake and partitioning has remained a challenge. To overcome this, we applied a high sensitivity gamma‐ray imaging system to image uptake and transport of radioactive 65 Zn in whole‐plant assays of Arabidopsis thaliana and the Zn hyperaccumulator Arabidopsis halleri . We show that our system can be used to quantitatively image and measure uptake and root‐to‐shoot translocation dynamics of zinc in real time. In the metal hyperaccumulator Arabidopsis halleri, 65 Zn uptake and transport from its growth media to the shoot occurs rapidly and on time scales similar to those reported in rice. In transgenic A. halleri plants in which expression of the zinc transporter gene HMA 4 is suppressed by RNA i, 65 Zn uptake is completely abolished.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Real‐time whole‐plant dynamics of heavy metal transport inArabidopsis halleriandArabidopsis thalianaby gamma‐ray imaging

et al. 2019

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“…It is generally accepted that the uptake of Zn from soil has at least four main mechanisms (see also Aucour et al, 2011;Caldelas et al, 2011;Houben et al, 2014;Jouvin et al, 2012;Tang et al, 2012 and references herein): (1) root-induced soil acidification and mobilization of soil Zn (Houben et al, 2014;Loosemore et al, 2004); (2) Zn adsorption on root cell wall (Hall, 2002); (3) non-specific Zn transfer through the plasma membrane into the root symplast via low-affinity transporters (Hacisalihoglu et al, 2001), or (4) Zn specific uptake by either ZIP proteins or phytosiderophores released by the plant roots to transfer the Fe/Zn complexes through the membrane (Claus et al, 2013). The present growth media are far from the Fe-or Zn-deficiency conditions, hence the release of siderophores by L. multiflorum roots was probably negligible (Rö mheld and Marschner, 1990).…”

Section: Species Differences In Zn Uptake Translocation and Isotope mentioning

confidence: 99%

Transpiration flow controls Zn transport in Brassica napus and Lolium multiflorum under toxic levels as evidenced from isotopic fractionation

Couder

Mattielli

Drouet

et al. 2015

Comptes Rendus. Géoscience

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A B S T R A C TStable zinc (Zn) isotope fractionation between soil and plant has been used to suggest the mechanisms affecting Zn uptake under toxic conditions. Here, changes in Zn isotope composition in soil, soil solution, root and shoot were studied for ryegrass (Lolium multiflorum L.) and rape (Brassica napus L.) grown on three distinct metal-contaminated soils collected near Zn smelters (total Zn 0.7-7.5%, pH 4.8-7.3). The Zn concentrations in plants reflected a toxic Zn supply. The Zn isotopic fingerprint of total soil Zn varied from À0.05% to +0.26 AE 0.02% (d 66 Zn values relative to the JMC 3-0749L standard) among soils, but the soil solution Zn was depleted in 66 Zn, with a constant Zn isotope fractionation of about À0.1% d 66 Zn unit compared to the bulk soil. Roots were enriched with 66 Zn relative to soil solution (d 66 Zn root À d 66 Zn soil solution = D 66 Zn root-soil solution = +0.05 to +0.2 %) and shoots were strongly depleted in 66 Zn relative to roots (D 66 Zn shoot-root = À0.40 to À0.04 %). The overall d 66 Zn values in shoots reflected that of the bulk soil, but were lowered by 0.1-0.3 % units as compared to the latter. The isotope fractionation between root and shoot exhibited a markedly strong negative correlation (R 2 = 0.83) with transpiration per unit of plant weight. Thus, the enrichment with light Zn isotopes in shoot progressed with increasing water flux per unit plant biomass dry weight, showing a passive mode of Zn transport by transpiration. Besides, the light isotope enrichment in shoots compared to roots was larger for rape than for rye grass, which may be related to the higher Zn retention in rape roots. This in turn may be related to the higher cation exchange capacity of rape roots. Our finding can be of use to trace the biogeochemical cycles of Zn and evidence the tolerance strategies developed by plants in Znexcess conditions.

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The rhizotoxicity of metal cations is related to their strength of binding to hard ligands

Kopittke

Menzies

Wang

et al. 2014

Enviro Toxic and Chemistry

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Mechanisms whereby metal cations are toxic to plant roots remain largely unknown. Aluminum, for example, has been recognized as rhizotoxic for approximately 100 yr, but there is no consensus on its mode of action. The authors contend that the primary mechanism of rhizotoxicity of many metal cations is nonspecific and that the magnitude of toxic effects is positively related to the strength with which they bind to hard ligands, especially carboxylate ligands of the cell-wall pectic matrix. Specifically, the authors propose that metal cations have a common toxic mechanism through inhibiting the controlled relaxation of the cell wall as required for elongation. Metal cations such as Al 3þ and Hg 2þ , which bind strongly to hard ligands, are toxic at relatively low concentrations because they bind strongly to the walls of cells in the rhizodermis and outer cortex of the root elongation zone with little movement into the inner tissues. In contrast, metal cations such as Ca 2þ , Na þ , Mn 2þ , and Zn 2þ , which bind weakly to hard ligands, bind only weakly to the cell wall and move farther into the root cylinder. Only at high concentrations is their weak binding sufficient to inhibit the relaxation of the cell wall. Finally, different mechanisms would explain why certain metal cations (for example, Tl þ , Ag þ , Cs þ , and Cu 2þ ) are sometimes more toxic than expected through binding to hard ligands. The data presented in the present study demonstrate the importance of strength of binding to hard ligands in influencing a range of important physiological processes within roots through nonspecific mechanisms. Environ Toxicol Chem 2014;33:268-277. # 2013 SETAC

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Zinc uptake and radial transport in roots of Arabidopsis thaliana: a modelling approach to understand accumulation

Cited by 54 publications

References 53 publications

Real‐time whole‐plant dynamics of heavy metal transport inArabidopsis halleriandArabidopsis thalianaby gamma‐ray imaging

Real‐time whole‐plant dynamics of heavy metal transport inArabidopsis halleriandArabidopsis thalianaby gamma‐ray imaging

Transpiration flow controls Zn transport in Brassica napus and Lolium multiflorum under toxic levels as evidenced from isotopic fractionation

The rhizotoxicity of metal cations is related to their strength of binding to hard ligands

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