The evolutionary ecology of fungal killer phenotypes

Abstract

Ecological interactions influence evolutionary dynamics by selecting upon fitness variation within species. Antagonistic interactions often promote genetic and species diversity, despite the inherently suppressive effect they can have on the species experiencing them. A central aim of evolutionary ecology is to understand how diversity is maintained in systems experiencing antagonism. In this review, we address how certain single-celled and dimorphic fungi have evolved allelopathic killer phenotypes that engage in antagonistic interactions. We discuss the evolutionary pathways to the production of lethal toxins, the functions of killer phenotypes and the consequences of competition for toxin producers, their competitors and toxin-encoding endosymbionts. Killer phenotypes are powerful models because many appear to have evolved independently, enabling across-phylogeny comparisons of the origins, functions and consequences of allelopathic antagonism. Killer phenotypes can eliminate host competitors and influence evolutionary dynamics, yet the evolutionary ecology of killer phenotypes remains largely unknown. We discuss what is known and what remains to be ascertained about killer phenotype ecology and evolution, while bringing their model system properties to the reader's attention.

The nightjar and the ant: a tale of a lose-lose game

“…Of all insects, ants (Formicidae) are the most abundant in most terrestrial ecosystems (Del Toro et al, 2012). There is ample literature documenting antagonistic ant-bird interactions, primarily in the form of bird predation on ants (reviewed in Avilés, 2023). There are also studies reporting negative effects of ants on aspects such as bird abundance, behaviour, and reproduction, primarily through predation on eggs and chicks (Alvarez-Blanco et al, 2020;Davis et al, 2008;Haemig, 1999).…”

The signal sequence of yeast killer toxin K2 confers producer self-protection and allows conversion into a modular toxin-antitoxin system

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