Natural selection drives population divergence for local adaptation in a wheat pathogen

Area of Science:

• Evolutionary biology
• Plant pathology
• Population genetics

Background:

• Agricultural pathogens evolve rapidly due to agro-ecosystem dynamics.
• Understanding pathogen adaptation is crucial for crop protection.

Purpose of the Study:

• To investigate the evolutionary forces driving population divergence in Parastagonospora nodorum.
• To determine adaptive strategies of P. nodorum to environmental changes like temperature and fungicides.

Main Methods:

• QST-FST comparison using 164 P. nodorum strains from eight global populations.
• Digital image analysis for growth rate and melanization measurements under varying temperatures and fungicide concentrations.
• Genome sequencing for FST calculations.

Main Results:

• All measured traits (growth rate, melanization) were under selection.
• Diversifying selection predominated for growth under fungicide and high-temperature stress.
• Stabilizing selection influenced growth at optimal temperatures and melanization.

Conclusions:

• P. nodorum populations exhibit significant evolutionary potential to adapt to local environmental changes.
• Adaptation mechanisms include trade-offs, such as between melanin production and growth under heat stress.
• Findings highlight the pathogen's capacity to evolve in response to agricultural management practices and climate change.