Microbial Multicellularity

In filamentous cyanobacteria such as Anabaena, a hallmark of multicellularity is the differentiation of heterocysts, specialized nitrogen-fixing factories. These cells appear at regular intervals of roughly one in ten vegetative cells, enabling the parallel execution of nitrogen fixation and photosynthesis—two otherwise incompatible processes. More broadly, Anabaena filaments exhibit deep integration: cells are linked by nano-channels for metabolite and signal exchange and are enclosed within a continuous outer membrane. Together, these features point to a capacity for cooperation that may extend well beyond nitrogen fixation.

Using spatial transcriptomics and live-imaging, we study the heterocyst developmental program and the cell–cell exchanges that sustain it at single-cell resolution. We are also exploring additional modes of differentiation and cooperation.