A relationship among fungicide-resistant phenotypes of Botrytis cinerea based on RAPD analysis

On the basis of the mode of spore germination and mycelial growth on fungicide-amended media, 200 Botrytis cinerea Pers.:Fr. single spore isolates were classified into six representative groups of resistant phenotypes. Sixty eight isolates were phenylcarbamate highly resistant (Pcm(HR), wild type), eight were dicarboximide moderately and phenylcarbamate highly resistant (Dic(MR)PCM(HR)), four were benzimidazole and phenylcarbamate highly resistant (Ben(HR)Pcm(HR)), five were dicarboximide and benzimidazole moderately resistant and phenylcarbamate highly resistant (Dic(MR)Ben(MR)Pcm(HR)), twenty were dicarboximide moderately and benzimidazole highly resistant (Dic(MR)Ben(HR)) and ninety five isolates were benzimidazole highly resistant (BENHR). Two representative isolates of each phenotype were examined by random amplified polymorphic DNA (RAPD) fingerprint analysis. Relationships among the isolates were determined using the unweighted pair-group method with arithmetic average (UPGMA) and dendrograms were constructed. Regardless of host, geographical origin and year of the isolation, phylogenetic analysis revealed the clear differentiation of the six phenotypic-resistant groups classified into three clusters. The first cluster included isolates of the Pcm(HR) phenotype with subdivisions included the wild type, the Dic(MR) and the Ben(HR) phenotypes. The latter two phenotypes maintained their wild type insensitivity to diethofencarb. This first cluster was branching with a second cluster that included the double resistance phenotypes Dic(MR)Ben(MR) and Dic(MR)Ben(HR). A third cluster, which was most distantly related to the above two included isolates of Ben(HR) only. The presented data show a positive correlation between conventional and molecular techniques in definition of fungicide-resistant phenotypes and support earlier findings of the genetically based diversity of fungicide resistance.