The suitability of random amplified polymorphic
DNA for identification of Pythium aphanidermatum
was investigated. Three
oligoprimers were selected after testing three isolates of
P. aphanidermatum and one isolate of P.
ultimum with a total of 40 primers.
The selected 10-mer primers were used with 20 isolates of
P. aphanidermatum, four isolates of P.
deliense, two isolates of P. ultimum,
two isolates of P. irregulare and one isolate of
P. paroecandrum. Most of the P.
aphanidermatum isolates (13 of 20), were obtained from
samples of Cucumis sativus, or water from
cucumber greenhouses. The three selected primers gave
identical fingerprints for 18 of the
20 P. aphanidermatum isolates, including all the
isolates from cucumbers. Two of the primers gave fingerprints
that could be used to
differentiate between isolates of the Pythium
species studied. The banding pattern of P.
aphanidermatum given by the third primer
could not easily be distinguished from the fingerprint of
P. deliense. However, when used in conjunction with
the other two primers,
the third primer can be used to verify the identity of
P. aphanidermatum.