Caister Academic Press

Bacterial Biofilms on Fungal Surfaces

Authors: Deborah A. Hogan, Matthew J. Wargo and Nancy Beck
Abstract: Bacterial biofilm formation on fungi participates in the synergistic degradation of substrates, antagonism of fungal growth, bacterial utilization of fungi as nutrient sources, and the formation of more complex synergistic associations for the purposes of nutrient acquisition. While bacterial biofilm formation has been described in many systems, the molecular mechanisms that govern these interactions are not yet well understood. Analysis of physical interactions between Pseudomonas aeruginosa and the dimorphic opportunistic fungal pathogen Candida albicans has provided insights into factors involved in attachment and matrix production, and has demonstrated a role for the bacterial quorum sensing molecule, 3-oxo-C12-homoserine lactone, within bacterial-fungal biofilms. Subsequent to P. aeruginosa biofilm formation on the fungus, extracellular bacterial products contribute to the death of the fungal hyphae. Studies focused on the interactions between bacteria and fungi in the phytosphere have illustrated additional processes that contribute to bacterial biofilm formation on fungi including bacterial chemotaxis towards fungal cells, the cross-feeding of nutrients between interacting species, and the expression of specific genes upon contact with fungal cells. By understanding bacterial biofilm formation on fungi, we will gain insight into economically important interactions, such as those involved in the bacterial biocontrol of fungal plant pathogens. Furthermore, using tractable bacterial-fungal biofilm model systems, we may uncover important elements of bacterial biofilms on other living surfaces such as plant and animal tissues.
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