Evidence for functional divergence in arbuscular mycorrhizal fungi from contrasting climatic origins

Authors

  • Pedro M. Antunes,

    1. Department of Biology, Algoma University, Sault Ste. Marie, ON, Canada, P6B 2G4
    2. Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
    3. Freie Universität Berlin, Institut für Biologie, Plant Ecology, Altensteinstr. 6, D-14195 Berlin, Germany
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    • These authors contributed equally to this work.

  • Alexander M. Koch,

    1. Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
    2. Biology and Physical Geography Unit, I.K. Barber School of Arts and Sciences, The University of British Columbia – Okanagan, SCI 311 – 3333 University Way, Kelowna, BC, Canada, V1V 1V7
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    • These authors contributed equally to this work.

  • Joseph B. Morton,

    1. West Virginia University, Morgantown, WV 26506-6108, USA
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  • Matthias C. Rillig,

    1. Freie Universität Berlin, Institut für Biologie, Plant Ecology, Altensteinstr. 6, D-14195 Berlin, Germany
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  • John N. Klironomos

    1. Department of Integrative Biology, University of Guelph, Guelph, ON, Canada, N1G 2W1
    2. Biology and Physical Geography Unit, I.K. Barber School of Arts and Sciences, The University of British Columbia – Okanagan, SCI 311 – 3333 University Way, Kelowna, BC, Canada, V1V 1V7
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Author for correspondence:
Pedro M. Antunes
Tel: + 1 705 9492301
Email: antunes@algomau.ca

Summary

  • A considerable amount of phenotypic, genetic and symbiotic functional variability has been documented in arbuscular mycorrhizal fungi (AMF). However, little is known about whether distinct AMF ecotypes have evolved within their geographic range. We tested the hypothesis that AMF growing at temperatures closer to those prevalent within their origin would benefit their host and grow more than isolates distant from their native conditions.
  • For each of six AMF species, we chose pairs of isolates that originated from distant areas with contrasting climates. Each isolate was grown in association with two grass species of different thermal optima at two temperature settings. Thus, we also tested whether AMF from different climatic origins were dependent on the thermal adaptation of the host plant species or to temperature per se.
  • Although fungal growth was not directly affected by temperature, we found that AMF isolates originating from contrasting climates consistently and differentially altered plant growth.
  • Our results suggest that AMF from contrasting climates have altered symbiotic function, thus linking an abiotic factor to ecotypic differentiation of putatively important symbionts.

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