Abstract:
Botrytis cinerea isolates collected from Niagara region were
treated with different concentrations of the fiingicide, iprodione to
test their sensitivity to this fungicide. These Botrytis cinerea isolates
were divided into two groups according to their sensitivity to
iprodione. Those isolates whose growth was inhibited by iprodione
at concentrations < 2|i,g/nil were classified as sensitive isolates.
Isolates that were able to show considerable growth at 2|j,g/ml
iprodione were classified as resistant isolates. Resistant and
sensitive isolates were compared for their morphological and growth
characteristics, conidial germination, virulence on grape berries and
protein banding profiles. The fungicide iprodione at a concentration
of 2|xg/nil inhibited mycelial growth, sporulation and conidial
germination of sensitive isolates but not those of resistant isolates.
The inhibitory effect of the fungicide was greater on mycelial growth
than on conidia germination of the sensitive isolates. Sensitive
isolates produced no sclerotia whereas resistant isolates produced
large number of sclerotia. The fungicide iprodione affected
sclerotial production in the resistant isolates. The number of
sclerotia was decreased by the increase of iprodione in the medium.
Sporulation of resistant isolates was improved significantly in the
presence of iprodione. The resistant isolates were as virulent as the
sensitive isolates on grape berries.
The sensitive and resistant isolates showed similar protein
banding profiles in the absence of iprodione in polyacrylamide gel
electrophoresis studies. Similar protein profiles were also observed
when these isolates were grown in the presence of low iprodione
concentration (0.5|ig/nil). However, in the presence of concentration (0.5|ig/nil). However, in the presence of iprodione at
concentration of 5|Xg/nil, one protein band with approximate
molecular weight of 83 KDa was present in the growing resistant
isolates (and the controls) but was missing in the inhibited sensitive
isolates.
