C. elegans interprets bacterial non-coding RNAs to learn pathogenic avoidance

Area of Science:

• Microbiology
• Genetics
• Neuroscience

Background:

• Caenorhabditis elegans must differentiate between food and pathogens.
• Bacterial exposure can influence worm behavior.

Purpose of the Study:

• To investigate the role of small RNAs in pathogen avoidance learning.
• To determine the mechanisms of transgenerational inheritance of avoidance behavior.

Main Methods:

• Exposure of C. elegans to pathogenic Pseudomonas aeruginosa (PA14) small RNAs.
• Assessing avoidance behavior in treated worms and subsequent generations.
• Investigating the involvement of RNA interference (RNAi), PIWI-interacting RNA (piRNA) pathways, germline, and ASI neurons.
• Identifying specific bacterial non-coding RNAs and their C. elegans targets.

Main Results:

• A single exposure to PA14 small RNAs induced pathogen avoidance in C. elegans.
• This learned avoidance was inherited across four subsequent generations.
• The RNAi and piRNA pathways, germline, and ASI neuron were essential for both the induced avoidance and its inheritance.
• A specific Pseudomonas aeruginosa non-coding RNA (P11) was necessary and sufficient for learned avoidance.
• The C. elegans gene maco-1 was identified as a target required for this avoidance behavior.

Conclusions:

• Small RNAs mediate learned pathogen avoidance in C. elegans.
• This learned behavior and its underlying molecular mechanisms are transgenerationally inherited.
• A non-coding RNA-dependent mechanism allows worms to sense and transmit information about microbial threats across generations.