Speaker
Description
Bacteria inhabit nearly every ecosystem, with critical implications for biogeochemistry, agriculture, and health. Many bacterial habitats are complex 3D environments, e.g., soils, hosts, and bodies of water, where they form spatially structured multicellular communities. This spatial organization is pivotal for community growth, cross-feeding, and diversity, and for withstanding challenges such as competing species, toxins, and bacteriophages—viruses that infect and kill bacteria. However, laboratory studies of well-mixed cultures and surface-attached colonies miss key spatial arrangements, ecological interactions, and defensive strategies that emerge in such environments. As a result, the collective dynamics and defensive capabilities of 3D bacterial colonies remain largely unknown, despite their prevalence in nature.
In this talk, I will first discuss how bacterial colonies acquire their shape in complex 3D environments. By integrating experiments with biophysical modeling, I will show how colonies growing in 3D transparent granular environments develop distinct architectures—driven by differential access to nutrients—that fundamentally differ from their flat-culture counterparts and are generic across species and environmental conditions. I then turn to phage–bacteria interactions in 3D and ask how anti-phage defense systems operate in such 3D-structured populations. Focusing on abortive infection systems, in which infected cells undergo programmed cell death to halt viral spread, I will show that spatial structure itself provides an additional layer of protection: anti-phage defense systems are significantly more effective in 3D structured communities than in well-mixed or flat-culture conditions.
Together, these findings show how spatial structure governs bacterial collective dynamics and function—from growth to anti-phage defense—and provide a quantitative framework for predicting and ultimately controlling microbial communities in realistic 3D environments, bridging simplified laboratory settings and natural ecosystems.
