Biofilm/Mat assays for budding yeast

Abstract

Many microbial species form biofilms/mats under nutrient-limiting conditions, and fungal pathogens rely on this social behavior for virulence. In budding yeast, mat formation is dependent on the mucin-like flocculin Flo11, which promotes cell-to-cell and cell-to-substrate adhesion in mats. The biofilm/mat assays described here allow the evaluation of the role of Flo11 in the formation of mats. Cells are grown on surfaces with different degrees of rigidity to assess their expansion and three-dimensional architecture, and the cells are also exposed to plastic surfaces to quantify their adherence. These assays are broadly applicable to studying biofilm/mat formation in microbial species.

FIGURE 1

Sample results from a biofilm/mat assay. When grown on medium containing a high agar concentration (YEPD medium containing 4% agar), wild-type cells (left) produce a ruffled pattern, whereas flo11Δ mutant cells (right) do not. Bar, 1 cm. Magnification, 3×.