PDA

Potato Dextrose Agar (PDA)

Potato Dextrose Agar is primarly used for the growth of the opportunistic fungal pathogen Scedosporium prolificans. Thus, it is mostly used in determining the bioactivity of actinomycete strains against Scedosporium.

Preparation

Per Litre:

• 4g Potato Extract
• 20g Dextrose
• 20g Agar
• 1L dH₂O

Instructions

1. Dissolve the potato extract and dextrose in the dH₂O
2. Into 10 250mL conical flasks, add 2g of agar to each flask
3. Into each flask, pour 100mL of the potato extract/dextrose solution
4. Autoclave

Uses

• Bioactivity of actinomycetes against S. prolificans. When being used in this manner, spot the actinomycete in the centre of the petri dish and incubate until sporulation. Then, streak a single straight line of S. prolificans along one side of the petri dish. Leave the plate 'upside down' (i.e. with the incolulated side of th media facing upwards) in a dark location. After a few days, look to see if the actinomycete has caused the S. prolificans to grow in a cresent shape or if the bacterial colony has been encroached upon by the fungus.

• Bioactivity of actinomycetes against the Take All fungus (Gaeumannomyces graminis var. tritici), in a similar method to that described above.