Pectinase Agar Plates

1% polygalacturonic acid (Fluka)

6.7 g/L yeast nitrogen base without amino acids

2 g/L ammonium sulfate

2% glucose (or 2% galactose; see below)

2% agar

Amino acids:

• 20 mg/L histidine

• 120 mg/L leucine

• 60 mg/L lysine

• 20 mg/L arginine

• 20 mg/L tryptophan

• 20 mg/L tyrosine

• 40 mg/L threonine

• 20 mg/L methionine

• 50 mg/L phenylalanine

20 mg/L uracil

20 mg/L adenine

50 mM potassium phosphate buffered solution (pH 8)

Use 2% galactose instead of 2% glucose to measure the induction of the filamentous growth pathway in response to glucose limitation. Include any additional amino acids that may be required for the growth of an auxotrophic strain. Prepare in H₂O. Heat the solution to 70°C with stirring for 30 min before autoclaving (polygalacturonic acid has low solubility in H₂O). Fill sterile Petri dishes with ∼25 mL of autoclaved medium.

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