Rapid evolution in a plant-pathogen interaction and the consequences for introduced host species

Area of Science:

• Plant pathology
• Evolutionary biology
• Ecology

Background:

• Plant species introduced to new regions face novel pathogens and can leave co-evolved ones behind.
• Infection and virulence traits in plants and pathogens can evolve rapidly.
• Understanding these evolutionary dynamics is crucial for managing invasive species and their associated diseases.

Purpose of the Study:

• To investigate how plant-fungal interactions change in an invasion context using Stemphylium solani and clover hosts.
• To explore the evolutionary potential of pathogens to adapt to new hosts.
• To assess host adaptation and tolerance in response to pathogen pressure.

Main Methods:

• Experimental serial passage of Stemphylium solani through multiple clover hosts over four generations.
• Comparative study of pathogen infection and virulence across native, naturalized, and introduced clover genotypes.
• Direct comparison of pathogen performance on familiar (California) versus unfamiliar (European) genotypes of naturalized clover species.

Main Results:

• Stemphylium solani consistently increased infection rates after serial passage, but damage to hosts did not consistently change.
• Significant variation in host susceptibility and pathogen virulence was observed among clover groups.
• The pathogen infected familiar California clover genotypes more frequently but caused less damage compared to unfamiliar European genotypes of the same species.

Conclusions:

• Results support the hypothesis of rapid adaptive evolution in both the pathogen (enhanced infectivity) and the host (increased tolerance).
• The study highlights the dynamic nature of plant-pathogen interactions and the potential for rapid evolutionary changes in invasion scenarios.
• These findings have implications for understanding and managing plant invasions and the associated ecological dynamics.