Microbial cooperation is a key driver of ecological and functional outcomes in both multispecies and clonal communities. Cooperative behaviors are essential to understand functionality among phenotypically diverse bacteria emerging in clonal populations The concept of cooperative virulence challenges the traditional view of pathogens as monolithic and isolated threats, highlighting how division of labor within clonal populations aids infection success, helping to overcome and even exploit host defenses. However, knowledge remains limited on how phenotypic variants emerge, contribute to cooperative behaviors, and affect functionality. Some open critical questions are: How does phenotypic heterogeneity arise and persist within clonal populations? How do different traits interact in a complex phenotypic landscape? What drives cooperative behaviors? How does these affect disease progression and spread? And how can this knowledge be applied to control disease and protect crops?

This project seeks to address these questions by investigating phenotypic heterogeneity and cooperative behavior in an academically and economically relevant plant pathogen: Pseudomonas syringae. By integrating advanced single-cell approaches to our knowhow and molecular tools in plant-bacterial interactions, this project aims to: 1. Investigate the molecular and environmental factors driving phenotypic variation across multiple traits. 2. Uncover Mechanisms of Cooperation by investigating how heterogeneity facilitates cooperative behaviors: how they relate to immune evasion, host colonization and spread. 3. Link Cooperative Behavior to Virulence by establishing how cooperative interactions within a phenotypically heterogeneous landscape in clonal population contribute to disease and increase pathogen resilience against environmental factors such as crop protection measures.

Building on our previous results obtained from curiosity-driven questions about phenotypic diversity and community behaviors, previously unexplored aspects of plant pathogens, this project centers on how phenotypic diversity emerges in pathogen populations and its relevance for disease and control. This will broaden microbial ecology knowledge and deepen our understanding of pathogens, particularly plant pathogens, while providing new insights for crop protection and sustainable disease management. This project tackles fundamental questions about pathogen adaptation, with significant implications for crop protection and food safety, and aligns with global efforts to secure food systems amid increasing agricultural and environmental challenges, addressing the societal need for food security.