Phenotypic plasticity segregates antagonistic species but undermines their coexistence
Environmental change often induces novel phenotypes in multiple cohabiting species, yet how such common-cue-induced plasticity shapes their coexistence is largely unknown. Testing this link requires disentangling inducing-environment effects from induced-phenotype effects, which remains elusive. We address this gap using two mutually antagonistic bacterial species, Staphylococcus aureus (Sa) and…
Environmental shifts can trigger new traits in coexisting species, but the extent to which such induced plasticity influences their coexistence remains unclear. Understanding this connection requires separating the impact of the changing environment from the effects of the induced traits. To tackle this challenge, researchers focused on two bacterial species known to be in opposition: Staphylococcus aureus (Sa) and Pseudomonas aeruginosa (Pa).
In low salinity conditions, where both bacteria exist as single cells, Pa was able to outcompete Sa. However, in high salinity environments, the bacteria evolved to form distinct structures: Sa formed filaments at the bottom, while Pa established mats at the top. This physical separation allowed Pa to dominate the high salinity conditions, resulting in 10 times higher rates of coexistence compared to low salinity.
Interestingly, when researchers physically prevented cell clustering in high salinity conditions, forcing the bacteria to coexist more closely, the rates of coexistence increased by a factor of 100. This counterintuitive result was due to the fact that Pa's ability to cluster in high salinity was beneficial for its survival, but it was detrimental to Sa.
By monopolizing oxygen in the cluster, Pa reduced Sa's ability to thrive, leading to a weakened overall coexistence. This phenomenon, where an adaptive trait aids one species at the expense of another, highlights the intricate nature of antagonistic coexistence.
Further investigation into the genomic makeup of the bacterial community in high salinity environments with segregated bacteria revealed that the absence of physical separation allowed for rapid, species-specific evolution. This finding underscores the complex interplay between environmental change, induced phenotypes, and coexistence dynamics. The study demonstrates that while plasticity can promote antagonistic coexistence, it can also undermine it by creating conditions that favor one species over another.
Written by urgent.news from bioRxiv's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
