A functional amyloid matrix underpins the PDIM-architected corded superstructure of the Mycobacterium tuberculosis biofilm

The architecture of Mycobacterium tuberculosis (Mtb) biofilms, associated with phenotypic drug tolerance, is poorly defined. Here, we reveal that these biofilms are highly organized corded superstructures, and in deconstructing their architecture, we provide a new molecular understanding of cording itself. Using multimodal imaging, we demonstrate that a functional amyloid matrix provides the fundamental structural integrity for the entire bacterial community. The lipid Phthiocerol Dimycocerosate (PDIM) directs the physical organization of these amyloid-encased bacilli into a foundational corded scaffold, while the ESX-1 secretion system contributes to the biochemical complexity of the extracellular matrix. This three-component model, which separates structural integrity, physical organization, and biochemical maturation, provides a new architectural paradigm that may inform strategies to overcome drug tolerance by dismantling these protective communities.