A keystone gene underlies the persistence of an experimental food web

Barbour et al., 2022. 

In the past few decades, the identification of keystone species, that is, those with essential roles in structuring a community or ecosystem, has increased across systems. Barbour et al. extended this concept to genes, showing that a single allele of a particular plant defense gene facilitates species coexistence across a small experimental trophic system. Specifically, plants with this allele grew faster, supporting larger populations of two species of herbivores and their predators. This finding suggests that genotype variation can play a role in the structure and function of organismal systems. 

Genes encode information that determines an organism’s fitness. Yet we know little about whether genes of one species influence the persistence of interacting species in an ecological community. Here, we experimentally tested the effect of three plant defense genes on the persistence of an insect food web and found that a single allele at a single gene promoted coexistence by increasing plant growth rate, which in turn increased the intrinsic growth rates of species across multiple trophic levels. Our discovery of a “keystone gene” illustrates the need to bridge between biological scales, from genes to ecosystems, to understand community persistence.

https://www.science.org/doi/epdf/10.1126/science.abf2232

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