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ORIGINAL RESEARCH article

Front. Microbiol.
Sec. Microbe and Virus Interactions with Plants
Volume 15 - 2024 | doi: 10.3389/fmicb.2024.1470469
This article is part of the Research Topic Mycorrhizal Symbioses: From Molecular and Functional Insights to Ecosystem Research and Application View all articles

The potential of strigolactones to shift competitive dynamics among two Rhizophagus irregularis strains

Provisionally accepted
Malin Klein Malin Klein 1,2*Corentin Bisot Corentin Bisot 3Loreto Oyarte Gálvez Loreto Oyarte Gálvez 1,3Vasilis Kokkoris Vasilis Kokkoris 1Thomas S. Shimizu Thomas S. Shimizu 3Lemeng Dong Lemeng Dong 2James Weedon James Weedon 1Harro Bouwmeester Harro Bouwmeester 2Toby Kiers Toby Kiers 1
  • 1 VU Amsterdam, Amsterdam, Netherlands
  • 2 University of Amsterdam, Amsterdam, Netherlands
  • 3 AMOLF Institute, Amsterdam, Netherlands

The final, formatted version of the article will be published soon.

    Strigolactones are phytohormones that influence arbuscular mycorrhizal fungal (AMF) spore germination, pre-symbiotic hyphal branching, and metabolic rates. Historically, strigolactone effects have been tested on single AMF strains. An open question is whether intraspecific variation in strigolactone effects and intraspecific interactions can influence AMF competition. Using the Rhizophagus irregularis strains A5 and C2, we tested for intraspecific variation in the response of germination and pre-symbiotic growth (i.e., hyphal length and branching) to the strigolactones GR24 and 5-deoxystrigol. We also tested if interactions between these strains modified their germination rates and pre-symbiotic growth. Spore germination rates were consistently high (> 90%) for C2 spores, regardless of treatment and the presence of the other strain. For A5 spores, germination was increased by strigolactone presence from approximately 30% to 70% but reduced when grown in mixed culture. When growing together, branching increased for both strains compared to monocultures. In mixed cultures, strigolactones increased the branching for both strains but led to an increase in hyphal length only for the strain A5. These strain-specific responses suggest that strigolactones may have the potential to shift competitive dynamics among AMF species with direct implications for the establishment of the AMF community.

    Keywords: strigolactones, arbuscular mycorrhizal fungi, rhizosphere, intraspecific variation, Intraspecific interaction, Germination, GR24, 5-Deoxystrigol

    Received: 25 Jul 2024; Accepted: 07 Oct 2024.

    Copyright: © 2024 Klein, Bisot, Oyarte Gálvez, Kokkoris, Shimizu, Dong, Weedon, Bouwmeester and Kiers. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Malin Klein, VU Amsterdam, Amsterdam, Netherlands

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