The five AhMTP1 zinc transporters undergo different evolutionary fates towards adaptive evolution to zinc tolerance in Arabidopsis halleri

Shahzad , Zaigham
        INRA
        , Montpellier .
         UMR 0386 Biochimie et Physiologie Moléculaire des Plantes; Gosti , F.
        . ISV Institut des sciences du végétal - bat. 23 Av de la terrasse 91198 GIF SUR YVETTE CEDEX FR; Frérot , H.
        . GEPV Génétique et évolution des populations végétales - Batiment SN2 59655 VILLENEUVE D ASCQ CEDEX FR; Lacombe , Éric
        INRA
        , Montpellier .
         UMR 0386 Biochimie et Physiologie Moléculaire des Plantes; Roosens , N.; Saumitou-Laprade , P.
        . GEPV Génétique et évolution des populations végétales - Batiment SN2 59655 VILLENEUVE D ASCQ CEDEX FR; Berthomieu , Pierre
        INRA
        , Montpellier .
         UMR 0386 Biochimie et Physiologie Moléculaire des Plantes

The five AhMTP1 zinc transporters undergo different evolutionary fates towards adaptive evolution to zinc tolerance in Arabidopsis halleri

2010

Shahzad , Zaigham (INRA , Montpellier (France). UMR 0386 Biochimie et Physiologie Moléculaire des Plantes) | Gosti , F. (Centre National de la Recherche Scientifique, GIF SUR YVETTE(France). ISV Institut des sciences du végétal - bat. 23 Av de la terrasse 91198 GIF SUR YVETTE CEDEX FR) | Frérot , H. (Centre National de la Recherche Scientifique, VILLENEUVE D ASCQ(France). GEPV Génétique et évolution des populations végétales - Batiment SN2 59655 VILLENEUVE D ASCQ CEDEX FR) | Lacombe , Éric (INRA , Montpellier (France). UMR 0386 Biochimie et Physiologie Moléculaire des Plantes) | Roosens , N. ( 1185 GEPV Génétique et évolution des populations végétales - Batiment SN2 59655 VILLENEUVE D ASCQ CEDEX FR) | Saumitou-Laprade , P. (Centre National de la Recherche Scientifique, VILLENEUVE D ASCQ(France). GEPV Génétique et évolution des populations végétales - Batiment SN2 59655 VILLENEUVE D ASCQ CEDEX FR) | Berthomieu , Pierre (INRA , Montpellier (France). UMR 0386 Biochimie et Physiologie Moléculaire des Plantes)

Gene duplication is a major mechanism facilitating adaptation to changing environments. From recent genomic analyses, the acquisition of zinc hypertolerance and hyperaccumulation characters discriminating Arabidopsis halleri from its zinc sensitive/non-accumulator closest relatives Arabidopsis lyrata and Arabidopsis thaliana was proposed to rely on duplication of genes controlling zinc transport or zinc tolerance. Metal Tolerance Protein 1 (MTP1) is one of these genes. It encodes a Zn(2+)/H(+) antiporter involved in cytoplasmic zinc detoxification and thus in zinc tolerance. MTP1 was proposed to be triplicated in A. halleri, while it is present in single copy in A. thaliana and A. lyrata. Two of the three AhMTP1 paralogues were shown to co-segregate with zinc tolerance in a BC1 progeny from a cross between A. halleri and A. lyrata. In this work, the MTP1 family was characterized at both the genomic and functional levels in A. halleri. Five MTP1 paralogues were found to be present in A. halleri, AhMTP1-A1, -A2, -B, -C, and -D. Interestingly, one of the two newly identified AhMTP1 paralogues was not fixed at least in one A. halleri population. All MTP1s were expressed, but transcript accumulation of the paralogues co-segregating with zinc tolerance in the A. halleri X A. lyrata BC1 progeny was markedly higher than that of the other paralogues. All MTP1s displayed the ability to functionally complement a Saccharomyces cerevisiae zinc hypersensitive mutant. However, the paralogue showing the least complementation of the yeast mutant phenotype was one of the paralogues co-segregating with zinc tolerance. From our results, the hypothesis that pentaplication of MTP1 could be a major basis of the zinc tolerance character in A. halleri is strongly counter-balanced by the fact that members of the MTP1 family are likely to experience different evolutionary fates, some of which not concurring to increase zinc tolerance.

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