A. Growth and colony phenotypes of loss and gain of function mutants in pacC on media of different pH. Wild type, pacCc and ΔpacC were assayed for ability to grow on PDA media buffered to different pH. For visualization of pH changes, the indicator Phenol Red was incorporated into the media, showing acidic (yellow) to basic (red) pH. Cultures were photographed after 5 days growth. B. Confrontation assays with R. solani. T. virens was coinoculated with R. solani by placing mycelial discs at the opposite sides of PDA plates. Overgrowth of R. solani by the different T. virens strains is evident from the production of green conidia; R. solani does not sporulate and appears white. The upper set of pictures was taken after 3 days, and the lower set after 12 days of growth. A, photos from above showing colony morphology and conidiation; B, photos from below showing pH gradients formed by the growing colonies.