A zinc-adapted fungus protects pines from zinc stress

Authors

  • Kristin Adriaensen,

    1. Centre of Environmental Sciences, Environmental Biology Group, Limburgs Universitair Centrum, Universitaire Campus, B-3590 Diepenbeek, Belgium;
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  • Daniël Van Der Lelie,

    1. Centre of Environmental Sciences, Environmental Biology Group, Limburgs Universitair Centrum, Universitaire Campus, B-3590 Diepenbeek, Belgium;
    2. Brookhaven National Laboratory, Biology Department, Building 463, Upton, New York 11973-5000, USA;
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  • André Van Laere,

    1. Laboratory of Developmental Biology, Institute of Botany and Microbiology, Katholieke Universiteit Leuven, Kasteelpark Arenberg 31, B-3001 Heverlee, Belgium
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  • Jaco Vangronsveld,

    1. Centre of Environmental Sciences, Environmental Biology Group, Limburgs Universitair Centrum, Universitaire Campus, B-3590 Diepenbeek, Belgium;
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  • Jan V. Colpaert

    Corresponding author
    1. Centre of Environmental Sciences, Environmental Biology Group, Limburgs Universitair Centrum, Universitaire Campus, B-3590 Diepenbeek, Belgium;
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Author for correspondence: Jan V. Colpaert Tel: +32 11 268304 Fax: +32 11 268301 Email: jan.colpaert@luc.ac.be

Summary

  • • Here we investigated zinc tolerance of ectomycorrhizal Scots pine (Pinus sylvestris) seedlings. An ectomycorrhizal genotype of Suillus bovinus, collected from a Zn-contaminated site and showing adaptive Zn tolerance in vitro, was compared with a nonadapted isolate from a nonpolluted area.
  • • A dose–response experiment was performed. Dynamics of plant and fungal development, and phosphate and ammonium uptake capacity, were assessed under increasing Zn stress. Effects of Zn on transpiration, nutrient content and Zn accumulation were analysed.
  • • Significant Zn–inoculation interaction effects were observed for several responses measured, including uptake rates of phosphate and ammonium; phosphorus, iron and Zn content in shoots; transpiration; biomass of external mycelia; and fungal biomass in roots.
  • • The Zn-tolerant S. bovinus genotype was particularly efficient in protecting pines from Zn stress. The growth of a Zn-sensitive genotype from a normal wild-type population was inhibited at high Zn concentrations, and this isolate could not sustain the pines’ acquisition of nutrients. This study shows that well adapted microbial root symbionts are a major component of the survival strategy of trees that colonize contaminated soils.

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