Restriction fragment length polymorphisms (RFLPs) were identified
among total DNA from clonal lines of Uncinula necator when
cloned sequences of total U. necator DNA were used as probes.
Four probes, pUnP14, pUnP27, pUnE21 and pUnE4, hybridized to
multiple-copy sequences and, with the exception of pUnE4, detected genetic
among clonal lines of U. necator. Clones
pUnP14, pUnP27 and pUnE4 produced banding patterns that were stable for
DNA extracted from different asexual generations of
U. necator clonal lines over at least 15 months. In addition,
were evaluated for species specificity. Clones pUnP27 and pUnE4
detected only U. necator sequences in total DNA from infected grapevine
Clones pUnP14 and pUnE4 did not hybridize to
total DNA from a range of fungi.
Genetic diversity in a sample of the Australian U. necator
population was investigated; 15 genotypes were identified among 29
U. necator clonal lines examined. Genetic variation was detected
in samples collected within micro-geographical areas, for example,
different genotypes representing both mating types of U. necator
were detected on a single plant of Vitis amurensis. RFLP analysis
the banding patterns produced using pUnP14, pUnP27 and pUnE21, identified
two broad genetic groups, designated A and B.
Analysis of DNA fragment patterns obtained using the polymerase chain
reaction (PCR) and the plant intron splice junction (ISJ)
primer R1 also supported the allocation of U. necator clonal
lines into groups A and B.