Antifungal susceptibility was measured in flat bottom, 96-well microtitre plates (Sarstedt #83.3924) using a broth microdilution protocol described in ref. 67. In brief, minimum inhibitory concentration (MIC) assays were set up in twofold serial dilutions of caspofungin or calcofluor white in a final volume of 200 µl per well. Caspofungin gradients were diluted either from 125 ng/ml down to 0.12 ng/ml or 2000 to 3.9 ng/ml. Calcofluor white gradients were diluted from 250 µg/ml down to 0.24 µg/ml. Where applicable, doxycycline was added to a final concentration of 0.1 µg/ml. Cell densities of overnight cultures were determined and dilutions were prepared such that ~103 cells were inoculated into each well. Plates were incubated in the dark at 30 °C for 48 h, at which point the absorbance was determined at 600 nm using a spectrophotometer (Molecular Devices) and corrected for background from the corresponding medium. Each strain was tested in duplicate in three biological replicates. MIC data was quantitatively displayed with color using the program Java TreeView 1.1.3 (http://jtreeview.sourceforge.net).