Step-Specific Adaptation and Trade-Off over the Course of an Infection by GASP Mutation Small Colony Variants.

Area of Science:

• Microbial pathogenesis
• Evolutionary biology
• Host-pathogen interactions

Background:

• Pathogens must adapt to sequential challenges within a host for successful transmission.
• Adaptations to one stage of infection may be detrimental in others, leading to trade-offs.
• Understanding these trade-offs is crucial for comprehending intrahost evolution and infection dynamics.

Purpose of the Study:

• To investigate step-specific adaptations in Xenorhabdus nematophila during Drosophila melanogaster infection.
• To explore the role of GASP (growth advantage in stationary phase) mutations in the lrp gene.
• To identify trade-offs between adaptations to different infection stages.

Main Methods:

• Utilized the Xenorhabdus nematophila and Drosophila melanogaster infection model.
• Analyzed the effects of lrp mutations, including nonsense mutations, on bacterial virulence.
• Assessed bacterial proliferation and immune resistance at different infection stages.

Main Results:

• Nonsense lrp mutations reduced resistance to the host immune response.
• All tested lrp mutations decreased early infection proliferation, correlating with diminished virulence.
• Reduced early proliferation was accompanied by enhanced late-stage proliferation, indicating a trade-off.

Conclusions:

• Step-specific adaptations, driven by lrp mutations, exist and involve trade-offs.
• Reduced early proliferation is a key factor in diminished virulence.
• These findings highlight the importance of considering stage-specific adaptations and their trade-offs in microbial evolution within hosts.