“Keystone” gene controls species diversity in experimental food web

In an experimental laboratory food web containing a wasp predator species, two aphid herbivore species, and the plant Arabidopsis, Matthew Barbour and colleagues found that a single Arabidopsis gene can affect the extinction risk and community collapse of the entire food web. Much like a keystone species that plays an essential role in the structure and survival of an ecosystem, this “keystone” gene is essential to the persistence of the food web. The finding can help explain why certain species coexist, “and tracing the ecological impact of specific genetic variants has the potential to transform how we act to conserve genetic and species diversity in a changing world,” the researchers write. In the food web set up by Barbour et al., a loss-of-function variant of the Arabidopsis gene AOP2, which produces a metabolite used in plant defense, had a pronounced effect on the food web’s persistence, significantly reducing the species’ extinction rate. Plants with this variant grew faster, allowing the aphids and wasp populations to grow as well. Patrik Nosil and Zach Gompert discuss these findings in a related Perspective.