Killer prey: Ecology reverses bacterial predation.

Area of Science:

• Microbial Ecology
• Evolutionary Biology
• Biotic Interactions

Background:

• Abiotic factors, such as temperature, significantly shape ecological interactions.
• Predator-prey relationships are fundamental to community structure, but their dynamics can be context-dependent.
• Examples of abiotic factors reversing predator-prey roles are rare, especially in microbial systems.

Purpose of the Study:

• To investigate how temperature influences predator-prey interactions between microbial species.
• To determine if temperature can reverse the roles of predator and prey.
• To explore the broader implications of such reversals in microbial communities.

Main Methods:

• Culturing Pseudomonas fluorescens at different temperatures (22°C and 32°C).
• Co-culturing P. fluorescens with the bacterial predator Myxococcus xanthus.
• Observing and quantifying the outcome of these interactions, including species survival and growth.

Main Results:

• Pseudomonas fluorescens reared at 32°C was preyed upon by Myxococcus xanthus.
• Pseudomonas fluorescens reared at 22°C became the predator, leading to the extinction of M. xanthus.
• Diffusible compounds from P. fluorescens also exhibited toxicity towards other microbial species.

Conclusions:

• Temperature is a critical abiotic factor that can reverse predator-prey dynamics in microbial communities.
• Microbial warfare, including predation, may be more common and variable across environmental gradients than previously recognized.
• These findings have significant ecological and evolutionary implications for understanding microbial community assembly and function.