Bacterial vitamin B₁₂ production enhances nematode predatory behavior

Area of Science:

• Microbiology
• Behavioral Ecology
• Nematology

Background:

• The gut microbiota influences host development, metabolism, and immunity.
• The impact of microorganisms on host behavior is an emerging area of research.
• Nematodes like Pristionchus pacificus offer model systems to study host-microbe interactions.

Purpose of the Study:

• To investigate how bacteria modulate complex behaviors in the nematode Pristionchus pacificus.
• To identify specific microbial factors responsible for behavioral changes.
• To explore the connection between microbiota, diet, and host behavior.

Main Methods:

• Culturing P. pacificus on various bacterial diets.
• Quantifying predatory efficiency against Caenorhabditis elegans.
• RNA sequencing (RNA-seq) to analyze host transcriptional responses.
• Screening bacterial mutants affecting vitamin B12 metabolism.

Main Results:

• Novosphingobium species significantly enhanced P. pacificus's predatory behavior (surplus killing).
• Bacterial production of vitamin B12 was identified as a key factor.
• Vitamin B12 supplementation amplified surplus killing, while B12-synthesis mutants reduced it.
• Metabolic rewiring was observed in P. pacificus upon exposure to Novosphingobium.

Conclusions:

• Host-associated microbiota can influence complex host behaviors.
• Bacterial vitamin B12 production is a significant modulator of predatory behavior in nematodes.
• This study highlights novel connections between animal diet, microbiota, and the nervous system.