Inference of symbiotic adaptations in nature using experimental evolution

Area of Science:

• Microbial Ecology
• Evolutionary Biology
• Symbiosis Research

Background:

• Recreating natural microbial interactions in laboratory settings is challenging.
• Understanding symbiotic adaptations requires studying microbes in their ecological context.
• Experimental evolution offers a way to infer past adaptations.

Purpose of the Study:

• To develop and validate a method for inferring symbiotic adaptations in microbes.
• To investigate the evolutionary history of interactions between Dictyostelium discoideum and its bacterial endosymbionts.
• To determine if bacterial endosymbionts have evolved to be less harmful over time.

Main Methods:

• Experimental evolution of microbes in isolation.
• Measuring fitness effects of evolved microbes on their symbiotic partners.
• Analyzing changes in trait expression to infer ancestral adaptations.
• Application to the Dictyostelium discoideum-Paraburkholderia symbiosis.

Main Results:

• The method successfully inferred lost symbiotic adaptations.
• Results suggest Paraburkholderia hayleyella has evolved to attenuate virulence.
• Dictyostelium discoideum showed evidence of evolving to antagonistically control Paraburkholderia growth.
• Paraburkholderia agricolaris did not show significant evidence of virulence attenuation.

Conclusions:

• The experimental evolution approach is effective for studying microbial adaptations in challenging contexts.
• Symbiotic relationships can involve complex evolutionary histories of cooperation and conflict.
• This method provides insights into the evolution of virulence and host control mechanisms in microbial symbioses.