P-321 - Effect of Multivariate Plant-Microbe Interactions in Host Disease Tolerance

Disease tolerance allows hosts to endure pathogen without severely impacting its fitness, bypassing growth-defense trade-off. Despite its relevance in wild and agricultural systems, mechanistic study of plant immunity largely focused on short-term resistance, overlooking ensuing growth and development in mitigating infection effects. Integrating the perspective of disease tolerance will enhance our understanding of plant-microbe interactions over hosts’ lifetime. The diverse host-associated microbes can modulate plant defense and infection outcomes. Co-infection with commensal bacteria and pathogens can protect hosts through niche competition. Using Arabidopsis thaliana and its phyllosphere Pseudomonads, we tracked infection progression over time, revealing host-genotype differences in acute symptoms and long-term recovery. Some initially showed necrosis but later accelerated growth, leading to recovery. Co-infection with both pathogenic and non-pathogenic Pseudomonas expedited recovery. We propose disease tolerance functions by limiting acute symptoms or accelerating post-infection recovery. Our research will dissect its molecular basis through host gene regulation, natural variation, and inter-microbial interactions. Combining synthetic microbial communities, RB-TnSeq, and metabolomics with ecological genomics, we aim to uncover core host regulatory response. This could guide strategies to enhance infection resilience and develop microbial-based bio-protective agents.