Extracellular matrix components are required to protect Bacillus subtilis from T6SS-dependent Pseudomonas invasion and modulate co-colonization of plants
Carlos Molina-Santiago, John R. Pearson, Yurena Navarro-García, María Victoria Berlanga-Clavero, Andrés Mauricio Caraballo-Rodriguez, Daniel Petras, Francisco M. Cazorla, Antonio de Vicente, Pieter C. Dorrestein, Diego Romero
Received Date: 13th September 2018
Bacteria adapt to environmental changes and interact with other microorganisms using a wide array of molecules, metabolic plasticity, secretion systems and the formation of biofilms. Some research has looked at changes in the expression of biofilm related genes during interactions between different bacterial species, however no studies have directly demonstrated the functional significance of biofilms in modulating such interactions. In this study, we have explored this fundamental question by studying the interaction between Bacillus subtilis 3610 and Pseudomonas chlororaphis PCL1606. We demonstrate the important role of the extracellular matrix in protecting B. subtilis colonies from infiltration by Pseudomonas. Surprisingly, we find that the Pseudomonas type VI secretion system (T6SS) is required in the cell-to-cell contact with matrix-impaired B. subtilis cells, revealing a novel role for T6SS against Gram-positive bacteria. In response to P. chlororaphis infiltration, we find that B. subtilis activates sporulation and expresses motility-related genes. Experiments using plant organs demonstrate the functional importance of these different bacterial strategies in their coexistence as stable bacterial communities. The findings described here further our understanding of the functional role played by biofilms in mediating bacterial social interactions.
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This is an abstract of a preprint hosted on an independent third party site. It has not been peer reviewed but is currently under consideration at Nature Communications.