Phase and antigenic variation govern competition dynamics through positioning in bacterial colonies

Area of Science:

• Microbiology
• Bacterial genetics
• Cellular dynamics

Background:

• Cellular positioning in bacterial colonies and biofilms influences dispersal, nutrient access, and stress resistance.
• The molecular mechanisms governing bacterial positioning remain largely uncharacterized.

Purpose of the Study:

• To investigate the role of type IV pilus (T4P) phase and antigenic variation in governing cellular positioning and bacterial fitness in Neisseria gonorrhoeae colonies.
• To test the hypothesis that T4P variation drives spatial segregation and confers a selective advantage.

Main Methods:

• Independent manipulation of growth rate and T4P-mediated interaction forces.
• Analysis of pilin gene sequencing in spatially segregated subpopulations.
• Spatio-temporal population dynamics investigation.

Main Results:

• Loss of T4P and subsequent segregation to the colony front confers a significant selective advantage.
• Pilin phase and antigenic variation create standing variation in pilin sequences.
• Non-piliated variants segregate to the front of growing colonies.

Conclusions:

• Tuning of attractive forces via pilin phase and antigenic variation is a key mechanism for bacterial colony dynamics.
• This variation promotes fitness by enabling advantageous cellular positioning.