Zhiyuan Li⏐ Peking University, China

An iron potluck: the eco-evolutionary dynamics in bacterial siderophore-interaction networks
Date
Feb 10, 2025, 12:30 pm1:30 pm
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Iron, despite its abundance in Earth's crust, remains a critical limiting nutrient for microbial growth due to its poor bioavailability. To acquire iron, most microbes produce siderophores — diverse small molecules with high iron-binding affinities. These siderophore-iron complexes are specifically recognized and uptaken by corresponding membrane receptors, effectively partitioning iron into distinct "sectors" accessible only to microbes with matching receptors.

Such universality, structural diversity, and recognition specificity of siderophore-mediated interactions create an "iron-net" across the microbial world, where widespread cross-species pirating drives evolutionary games. Utilizing sequence co-evolution, we successfully predicted community-level iron interactions in Pseudomonas with over 90% experimental validation accuracy, revealing distinct iron acquisition strategies between pathogenic and non-pathogenic species. Through consumer-resource models, we proved that intermediate levels of siderophore piracy maximize dynamical coexistence, and extensive participation in the "iron-potluck" characterizes non-pathogenic communities. Furthermore, our eco-evolutionary model illustrates how the dual selective pressures, i.e. exploiting others' siderophores while protecting one's own, drive continuous chemical innovation in iron networks, exemplifying the concept of the "adjacent possible" in biological systems.