Colony morphologies of U. maydis adr1 suppressor mutants. The wild-type 518 strain has a yeastlike colony morphology, and the adr1 mutant (deficient in the PKA catalytic subunit) is constitutively filamentous. The colony morphology of the selected mutants 10-2, 33-1, 218-1, uv14, 233-1, 113-2, and 228-1 range from completely yeastlike to slightly filamentous.