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Spatial genetic structure within a metallicolous population of Arabidopsis halleri, a clonal, self-incompatible and heavy-metal-tolerant species

Authors

  • FABIENNE VAN ROSSUM,

    1. Laboratoire de Génétique et Evolution des Populations Végétales, UMR CNRS 8016, FR CNRS 1818, Université de Lille 1, Bâtiment SN2, F-59655 Villeneuve d’Ascq Cedex, France
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    • *

      Present address: Plant Science and Nature Management, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.

  • ISABELLE BONNIN,

    1. Laboratoire de Génétique et Evolution des Populations Végétales, UMR CNRS 8016, FR CNRS 1818, Université de Lille 1, Bâtiment SN2, F-59655 Villeneuve d’Ascq Cedex, France
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    • Present address: UMR de Génétique Végétale (CNRS-INRA-UPS-INAPG), Ferme du Moulon, F-91190 Gif sur Yvette, France.

  • STÉPHANE FÉNART,

    1. Laboratoire de Génétique et Evolution des Populations Végétales, UMR CNRS 8016, FR CNRS 1818, Université de Lille 1, Bâtiment SN2, F-59655 Villeneuve d’Ascq Cedex, France
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  • MAXIME PAUWELS,

    1. Laboratoire de Génétique et Evolution des Populations Végétales, UMR CNRS 8016, FR CNRS 1818, Université de Lille 1, Bâtiment SN2, F-59655 Villeneuve d’Ascq Cedex, France
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  • DANIEL PETIT,

    1. Laboratoire de Génétique et Evolution des Populations Végétales, UMR CNRS 8016, FR CNRS 1818, Université de Lille 1, Bâtiment SN2, F-59655 Villeneuve d’Ascq Cedex, France
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  • PIERRE SAUMITOU-LAPRADE

    Corresponding author
    1. Laboratoire de Génétique et Evolution des Populations Végétales, UMR CNRS 8016, FR CNRS 1818, Université de Lille 1, Bâtiment SN2, F-59655 Villeneuve d’Ascq Cedex, France
      Pierre Saumitou-Laprade. Fax: +33 320 436 979; E-mail: pierre.saumitou-laprade@univ-lille1.fr
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Pierre Saumitou-Laprade. Fax: +33 320 436 979; E-mail: pierre.saumitou-laprade@univ-lille1.fr

Abstract

Arabidopsis halleri, a close wild relative of A. thaliana, is a clonal, insect-pollinated herb tolerant to heavy metals (Zn, Pd, Cd) and a hyperaccumulator of Zn and Cd. It is of particular interest in the study of evolutionary processes and phytoremediation. However, little is known about its population gene flow patterns and the structure of its genetic diversity. We used five microsatellite loci to investigate the genetic structure at a fine spatial scale (10 cm to 500 m) in a metallicolous population of A. halleri. We also studied the contributions made by clonal propagation and sexual reproduction (seed and pollen dispersal) to the genetic patterns. Clonal diversity was high (DG > 0.9). Clonal spread occurs only at short distances (< 1 m). Both clonal spread and limited dispersal, associated with sexual reproduction, contribute to the significant spatial genetic structure revealed by spatial autocorrelation analysis. The shape of the autocorrelogram suggests that seed dispersal is restricted and pollen flow extensive, which may be related to intense activity by insect pollinators. Clonal spread was more extensive in the lowly polluted zone than in the highly polluted zone. This cannot be interpreted as a strategy for promoting the propagation of adapted genotypes under the harshest ecological constraints (highest heavy metal concentrations). The higher fine-scale spatial genetic structure found in the lowly polluted zone can be ascribed to plant densities that were lower than in the highly polluted zone. No evidence of genetic divergence due to spatial heavy metal heterogeneity was found between lowly and highly polluted zones.

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