Reference : Functional analysis of the three HMA4 copies of the metal hyperaccumulator Arabidopsi...
Scientific journals : Article
Life sciences : Phytobiology (plant sciences, forestry, mycology...)
http://hdl.handle.net/2268/181581
Functional analysis of the three HMA4 copies of the metal hyperaccumulator Arabidopsis halleri
English
Nouet, Cécile mailto [Université de Liège > Département des sciences de la vie > Département des sciences de la vie >]
Charlier, Jean-Benoit [> >]
Carnol, Monique mailto [Université de Liège > Département de Biologie, Ecologie et Evolution > Ecologie végétale et microbienne >]
Bosman, Bernard mailto [Université de Liège > Département de Biologie, Ecologie et Evolution > Ecologie végétale et microbienne >]
Farnir, Frédéric mailto [Université de Liège > Département de productions animales > Biostatistiques et bioinformatique appliquées aux sc. vétér. >]
Motte, Patrick mailto [Université de Liège > Département des sciences de la vie > Génomique fonctionnelle et imagerie moléculaire végétale >]
Hanikenne, Marc mailto [Université de Liège > Département des sciences de la vie > Génomique fonctionnelle et imagerie moléculaire végétale >]
2015
Journal of Experimental Botany
Oxford University Press
66
5783-95
Yes (verified by ORBi)
International
0022-0957
1460-2431
Oxford
United Kingdom
[en] In Arabidopsis halleri, the AhHMA4 gene has an essential function in Zn/Cd hypertolerance and hyperaccumulation by mediating root to shoot translocation of metals. Constitutive high expression of AhHMA4 results from a tandem triplication and cis-activation of the promoter of all three copies. The three AhHMA4 copies possess divergent promoter sequences, but highly conserved coding sequences, and display identical expression profiles in the root and shoot vascular system. Here, we expressed an AhHMA4::GFP fusion under the control of each three A. halleri HMA4 promoters in a hma2hma4 double mutant of Arabidopsis thaliana to individually examine the function of each A. halleri AhHMA4 copy. The protein localized non-polarly at the plasma membrane of the root pericycle cells of both A. thaliana and A. halleri. The expression of each AhHMA4::GFP copy complemented the severe Zn deficiency phenotype of the hma2hma4 mutant by restoring root-to-shoot translocation of zinc. However, each copy had different impact on metal homeostasis in the A. thaliana genetic background: AhHMA4 copies 2 and 3 were more highly expressed and provided higher Zn tolerance in roots and accumulation in shoots than copy 1, whereas AhHMA4 copy 3 also increased Cd tolerance in roots. Our data suggest a certain extent of functional differentiation among the three A. halleri HMA4 copies, stemming from differences in expression levels rather than in expression profile. HMA4 is a key node of the Zn homeostasis network and small changes in expression level can have major impact on Zn allocation to root or shoot tissues.
Researchers
http://hdl.handle.net/2268/181581

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