Neutral genetic structuring of pathogen populations during rapid adaptation

Area of Science:

• Population Genetics
• Evolutionary Biology
• Plant Pathology

Background:

• Pathogen adaptation to new hosts involves complex demographic and selective pressures.
• Understanding the genetic signatures of rapid adaptation and host resistance overcoming is crucial.
• Stochasticity in founding events complicates predictions of evolutionary trajectories.

Purpose of the Study:

• To develop a demogenetic model for pathogen population dynamics and genetic evolution.
• To investigate eco-evolutionary dynamics in pathogens adapting to susceptible and resistant hosts.
• To identify distinct scenarios of pathogen adaptation based on life cycle and demographic factors.

Main Methods:

• Development of a demogenetic model incorporating pathogen population dynamics and genetic evolution.
• Simulation of pathogen life cycles with and without host alternation (susceptible and resistant hosts).
• Application of time-series clustering to identify distinct eco-evolutionary scenarios.

Main Results:

• Identified three main adaptation scenarios: minor genetic/demographic changes, founder effect on resistant host influencing susceptible host, and evolutionary rescue preceded by a bottleneck.
• Host alternation in life cycles increases the likelihood of evolutionary rescue.
• Demographic trajectories significantly shape genetic structure, with resistance-overcoming signatures often being transient (vanishing within years).

Conclusions:

• Pathogen adaptation to new hosts is characterized by diverse eco-evolutionary dynamics.
• Life cycle and demographic history are critical determinants of evolutionary trajectories and genetic structure.
• Accurate deciphering of pathogen evolution requires consideration of time-series data due to the transient nature of adaptation signatures.