Two-step infection processes can lead to coevolution between functionally independent infection and resistance...

Area of Science:

• Evolutionary Biology
• Microbial Ecology
• Genetics

Background:

• Pathogen infection involves multiple sequential steps.
• The impact of these multistep processes on host-pathogen coevolution remains poorly understood.
• Existing models often simplify infection dynamics, overlooking crucial sequential interactions.

Purpose of the Study:

• To develop a coevolutionary model for multistep host-pathogen interactions.
• To investigate how different genetic models for infection steps (inverse-gene-for-gene and gene-for-gene) affect coevolutionary dynamics.
• To identify patterns of selection and gene frequency changes in response to multistep infections.

Main Methods:

• Development of a novel coevolutionary model incorporating two distinct infection steps.
• Application of inverse-gene-for-gene (IGFG) genetics for host recognition/location.
• Application of gene-for-gene (GFG) genetics for host exploitation and immune evasion.

Main Results:

• Coevolutionary dynamics can lead to coupled gene frequency changes across the two infection steps.
• Selection favors pathogens infective at the IGFG step (recognition/location).
• Selection favors hosts resistant at the GFG step (exploitation/evasion).

Conclusions:

• Multistep infection processes create signals of positive selection between functionally independent genetic systems.
• These findings highlight the importance of considering sequential infection steps in host-pathogen coevolution.
• The study provides a new framework for understanding the evolutionary consequences of complex host-pathogen interactions.