A. parasiticus D8D3, an isogenic strain derived from the
wild-type aflatoxin producer A. parasiticus SU-1 (ATCC
56775), contains the GUS (uidA; encodes b-D-glucuronidase)
reporter fused to the nor-1 promoter (Chiou et al.,
2002).
Stocks of D8D3 conidiospores were prepared and stored
frozen (80 1C) until use as described previously (Chiou et
al., 2002). Spore concentrations ranging from 102 to
105 conidiospores/g peanuts were inoculated onto peanuts,
depending on the experiment. Spores were diluted with
sterile, deionized, distilled water (ddH2O) to achieve the desired spore concentration. One hundred microliters of
the diluted spore suspension was added to 4 g of peanuts in
a sterile, conical centrifuge tube; spores and peanuts were
mixed by light agitation. Inoculated peanuts were then
placed into a sterile Petri plate lined with sterile filter paper.
Uninoculated peanuts incubated under the same conditions
served as the negative control. Two milliliters of sterile,
ddH2O were added to wet the filter paper prior to adding
the inoculated peanuts.