FIG. 3.

Pseudohyphal growth induction on sucrose in nitrogen-rich medium and in the mep2Δ/mep2Δ mutant. (A) Sucrose induces pseudohyphal growth in nitrogen-rich medium, and this effect is dependent on Gpr1. Cells were grown overnight on minimal drop-out medium (S-URA) containing 5 g/liter ammonium sulfate or on complex YP medium. WT, wild type. (B) Sucrose (sucr), as opposed to glucose (glc), induced pseudohyphal growth in the mep2Δ/mep2Δ strain on nitrogen limitation medium, and this effect was dependent on Gpr1. (C) Maltose does not induce pseudohyphal growth on complex YP medium (YPM). SLAM, nitrogen limitation medium with maltose. (D) Sucrose and maltose are equally potent inducers of pseudohyphal growth on nitrogen-rich medium when the cells are provided with the same cAMP level. A homozygous cyr1Δ yak1Δ pde2Δ mutant was grown on nitrogen-rich minimal drop-out medium (S-URA) supplemented with sucrose or maltose for 24 h. Intracellular cAMP concentrations were controlled by the addition of extracellular cAMP as indicated. (E) Pseudohyphal growth was induced by 100 mM sucrose on nitrogen-rich complex medium (YPS) in a wild-type strain, but not in a mep2Δ/mep2Δ mutant.