References of "Krämer, Ute"
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See detailComplex regulation of the FRD3 gene in Arabidopsis relatives
Charlier, Jean Benoit; Polese, Catherine ULg; Nouet, Cécile ULg et al

Poster (2014, March 31)

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See detailComplex regulation of the FRD3 gene in Arabidopsis relatives
Charlier, Jean-Benoit ULg; Polese, Catherine ULg; Nouet, Cécile ULg et al

Poster (2013, February 26)

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See detailHard Selective Sweep and Ectopic Gene Conversion in a Gene Cluster Affording Environmental Adaptation
Hanikenne, Marc ULg; Kroymann, Juergen; Trampczynska, Aleksandra et al

in PLoS Genetics (2013), 9

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See detailPromoter analysis of three HMA4 gene copies in the zinc hyperaccumulator Arabidopsis halleri
Nouet, Cécile ULg; Cebula, Justyna; Motte, Patrick ULg et al

Poster (2012, September 20)

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See detailZinc hyperaccumulation: a model to examine metal homeostasis in plants
Hanikenne, Marc ULg; Nouet, Cécile ULg; Charlier, Jean-Benoit et al

Conference (2012, September 20)

The plant Arabidopsis halleri exhibits naturally selected metal hypertolerance and extraordinarily high levels of leaf metal accumulation. Metal hyperaccumulator species attract interest as they represent ... [more ▼]

The plant Arabidopsis halleri exhibits naturally selected metal hypertolerance and extraordinarily high levels of leaf metal accumulation. Metal hyperaccumulator species attract interest as they represent an extreme end of natural variation of the metal homeostasis network. This might be useful to reveal the global functioning of metal homeostasis networks and uncover key nodes whose alterations can drastically modify metal accumulation and tolerance. In addition, metal hyperaccumulation is a compelling model to study adaptation. In the last few years, major progress has been achieved in our understanding of the mechanisms underlying metal hyperaccumulation in A. halleri. High rates of metal uptake by roots, root-to-shoot translocation and efficient shoot vacuolar sequestration play central roles in determining hyperaccumulation and hypertolerance. Enhanced functions of several metal transporter-encoding genes result from gene copy number amplification and/or (cis)-regulatory changes. We will describe the function of several transporters in zinc and cadmium hyperaccumulation and hypertolerance, and in the adjustment of nutrient homeostasis in A. halleri. Recent work aiming to determine if selection acted during the evolutionary history of A. halleri on a loci required for metal tolerance and accumulation will be presented. [less ▲]

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See detailEvolution of Metal Hyperaccumulation in Arabidopsis halleri
Hanikenne, Marc ULg; Kroymann, Juergen; Bernal, Maria et al

Conference (2012, February 06)

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See detailMetal response of transgenic tomato plants expressing P1B-ATPase
Barabasz, Anna; Wilkowska, Anna; Ruszczyńska, Anna et al

in Physiologia Plantarum (2012), 145

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See detailPromoter analysis of the three HMA4 copies in the zinc hyperaccumulator Arabidopsis halleri
Nouet, Cécile ULg; Cebula, Justyna; Motte, Patrick ULg et al

Poster (2011, August)

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See detailExpression of the metal homeostasis gene FRD3 in two Arabidopsis species
Charlier, Jean-Benoît ULg; Polese, Catherine ULg; Krämer, Ute et al

Poster (2011, August)

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See detailMetal accumulation in tobacco expressing Arabidopsis halleri metal hyperaccumulation gene depends on external supply.
Barabasz, Anna; Krämer, Ute; Hanikenne, Marc ULg et al

in Journal of Experimental Botany (2010), 61(11), 3057-67

Engineering enhanced transport of zinc to the aerial parts of plants is a major goal in bio-fortification. In Arabidopsis halleri, high constitutive expression of the AhHMA4 gene encoding a metal pump of ... [more ▼]

Engineering enhanced transport of zinc to the aerial parts of plants is a major goal in bio-fortification. In Arabidopsis halleri, high constitutive expression of the AhHMA4 gene encoding a metal pump of the P(1B)-ATPase family is necessary for both Zn hyperaccumulation and the full extent of Zn and Cd hypertolerance that are characteristic of this species. In this study, an AhHMA4 cDNA was introduced into N. tabacum var. Xanthi for expression under the control of its endogenous A. halleri promoter known to confer high and cell-type specific expression levels in both A. halleri and the non-hyperaccumulator A. thaliana. The transgene was expressed at similar levels in both roots and shoots upon long-term exposure to low Zn, control, and increased Zn concentrations. A down-regulation of AhHMA4 transcript levels was detected with 10 muM Zn resupply to tobacco plants cultivated in low Zn concentrations. In general, a transcriptional regulation of AhHMA4 in tobacco contrasted with the constitutively high expression previously observed in A. halleri. Differences in root/shoot partitioning of Zn and Cd between transgenic lines and the wild type were strongly dependent on metal concentrations in the hydroponic medium. Under low Zn conditions, an increased Zn accumulation in the upper leaves in the AhHMA4-expressing lines was detected. Moreover, transgenic plants exposed to cadmium accumulated less metal than the wild type. Both modifications of zinc and cadmium accumulation are noteworthy outcomes from the biofortification perspective and healthy food production. Expression of AhHMA4 may be useful in crops grown on soils poor in Zn. [less ▲]

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See detailEvolution of metal hyperaccumulation in Arabidopsis halleri
Hanikenne, Marc ULg; Kroymann, Juergen; Talke, Ina N. et al

Conference (2009, March 04)

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See detailEvolution of metal hyperaccumulation required cis-regulatory changes and triplication of HMA4
Hanikenne, Marc ULg; Talke, Ina N.; Haydon, Michael J. et al

in Nature (2008), 453

Little is known about the types of mutations underlying the evolution of species-specific traits. The metal hyperaccumulator Arabidopsis halleri has the rare ability to colonize heavy-metal-polluted soils ... [more ▼]

Little is known about the types of mutations underlying the evolution of species-specific traits. The metal hyperaccumulator Arabidopsis halleri has the rare ability to colonize heavy-metal-polluted soils, and, as an extremophile sister species of Arabidopsis thaliana, it is a powerful model for research on adaptation. A. halleri naturally accumulates and tolerates leaf concentrations as high as 2.2% zinc and 0.28% cadmium in dry biomass. On the basis of transcriptomics studies, metal hyperaccumulation in A. halleri has been associated with more than 30 candidate genes that are expressed at higher levels in A. halleri than in A. thaliana. Some of these genes have been genetically mapped to broad chromosomal segments of between 4 and 24 cM co-segregating with Zn and Cd hypertolerance. However, the in planta loss-of-function approaches required to demonstrate the contribution of a given candidate gene to metal hyperaccumulation or hypertolerance have not been pursued to date. Using RNA interference to downregulate HMA4 (HEAVY METAL ATPASE 4) expression, we show here that Zn hyperaccumulation and full hypertolerance to Cd and Zn in A. halleri depend on the metal pump HMA4. Contrary to a postulated global trans regulatory factor governing high expression of numerous metal hyperaccumulation genes, we demonstrate that enhanced expression of HMA4 in A. halleri is attributable to a combination of modified cis-regulatory sequences and copy number expansion, in comparison to A. thaliana. Transfer of an A. halleri HMA4 gene to A. thaliana recapitulates Zn partitioning into xylem vessels and the constitutive transcriptional upregulation of Zn deficiency response genes characteristic of Zn hyperaccumulators. Our results demonstrate the importance of cis-regulatory mutations and gene copy number expansion in the evolution of a complex naturally selected extreme trait. The elucidation of a natural strategy for metal hyperaccumulation enables the rational design of technologies for the clean-up of metal-contaminated soils and for bio-fortification. [less ▲]

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See detailArabidopsis halleri, a model system to understand zinc homeostasis in plants
Hanikenne, Marc ULg; Talke, Ina N.; Hamilton, Christopher ULg et al

Poster (2007, November 16)

Detailed reference viewed: 16 (1 ULg)