Molecular and Pathological Variability Associated with Transposable Elements of Botrytis Cinerea Isolates Infecting Grape and Strawberry in Egypt

Grey mold caused by Botrytis cinerea, is known to cause great losses in most vegetable and fruit crops. Fifty-one isolates of B. cinerea were collected from grape (BCG) and strawberry (BCS) grown in different Egyptian locations. Variation among isolates was demonstrated using fenhexamid resistance and genetic approaches. Isolates were classified into various pathogenic groups depending on their reactions towards lettuce leaves. Genetic variability was identified in all isolates using transposable elements (TEs) analysis which revealed either the presence or absence of boty and flipper transposons. Furthermore, TEs typing of B. cinerea isolates demonstrated four TE types, on the basis of TE distribution in B. cinerea populations, namely, transposa (having both boty and flipper), flipper (possessing only flipper), boty (having only boty), and vacuma (lacking both boty and flipper elements). Transposa type was predominant (43.1%) and both transposa and vacuma isolate types showed no specialization with respect to host plant or plant location, while flipper type revealed a geographical preference in (BCG) isolates. Pathogenicity was also correlated to TE type as isolates containing transposa type revealed some degree of correlation with virulence behaviour, suggesting that transposa populations have higher pathogenic potential as compared to vacuma ones. The sensitivity of sampled isolates was tested against fenhexamid as one of the most important botryticides. Sensitivity to fenhexamid was shown in all isolates from strawberry and grape, grown in different locations, with low EC50 values between 0.012-0.084 μg/ml. This finding provided a cue for effective usage of fenhexamid for grey mold management. The present work demonstrated a correlation between the distribution of TEs and some fungal features such as isolate source and virulence, but no correlation was found between morphological characteristics, TE type, and sensitivity to fenhexamid. Cluster analysis based on phylogenetic tree showed that the Egyptian isolates branched as a separate divergent group from the others retrieved from GenBank, reflecting the presence of sequence polymorphism between the current isolates of B. cinerea and those previously identified.