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Assortative mating in sympatric ascomycete fungi revealed by experimental fertilizations.
Journal article

Assortative mating in sympatric ascomycete fungi revealed by experimental fertilizations.

  • Treindl AD Plant Ecological Genetics, Institute of Integrative Biology, ETH Zurich, Zürich, Switzerland.
  • Leuchtmann A Plant Ecological Genetics, Institute of Integrative Biology, ETH Zurich, Zürich, Switzerland. Electronic address: adrian.leuchtmann@env.ethz.ch.
  • 2019-08-17
Published in:
  • Fungal biology. - 2019
Endophytes
Epichloë
Reproductive barriers
Speciation
Spermatia competition
Biological Evolution
Endophytes
Epichloe
Genes, Mating Type, Fungal
Poaceae
Reproduction
Reproductive Isolation
Spores, Fungal
English Mate recognition mechanisms resulting in assortative mating constitute an effective reproductive barrier that may promote sexual isolation and speciation. While such mechanisms are widely documented for animals and plants, they remain poorly studied in fungi. We used two interfertile species of Epichloë (Clavicipitaceae, Ascomycota), E. typhina and E. clarkii, which are host-specific endophytes of two sympatrically occurring grasses. The life cycle of these obligatory outcrossing fungi entails dispersal of gametes by a fly vector among external fungal structures (stromata). To test for assortative mating, we mimicked the natural fertilization process by applying mixtures of spermatia from both species and examined their reproductive success. Our trials revealed that fertilization is non-random and preferentially takes place between conspecific mating partners, which is indicative of assortative mating. Additionally, the viability of hybrid and non-hybrid ascospore offspring was assessed. Germination rates were lower in E. clarkii than in E. typhina and were reduced in ascospore progeny from treatments with high proportions of heterospecific spermatia. The preferential mating between conspecific genotypes and reduced hybrid viability represent important reproductive barriers that have not been documented before in Epichloë. Insights from fungal systems will deepen our understanding of the evolutionary mechanisms leading to reproductive isolation and speciation.
Language
  • English
Open access status
closed
Identifiers
Persistent URL
https://sonar.ch/global/documents/3462
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