Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/25/2002
Publication Date: 2/2/2003
Citation: Lebeda, A., Widrlechner, M.P. 2003. Differentiation of Pseudoperonospora cubensis (cucurbit downy mildew) pathogenicity. Abstracts of the 8th International Congress of Plant Pathology, Christchurch, New Zealand, 2-7 February. Abstract 634, Host/pathogen Interaction Session. (unpaged)
Technical Abstract: Cucurbit downy mildew (Pseudoperonospora cubensis) has been a serious problem on cucumbers (Cucumis sativus) in Central Europe since 1984. The pathogen is characterized by its broad host range and large variation in pathogenicity. However, information about pathogenic variation of P. cubensis in Europe and other continents was incomplete. A well-characterized, comprehensive set of differential genotypes had not yet been developed. Recently, was proposed a set of differentials including 12 genotypes from six Cucurbitaceae genera (Benincasa, Citrullus, Cucumis, Cucurbita, Lagenaria, Luffa). The members of this set are well characterized and available as genebank accessions. A set of more than 20 P. cubensis isolates originating from the Czech Republic, France, Spain and The Netherlands was used for screening and differentiation of pathotypes. They were delimited on the basis of host specificities at the genus, species and intraspecific level. The results showed large variation in pathogenicity, and we distinguished at least twelve distinct pathotypes among the studied set of isolates. Pathotypes were then assigned unique tetrade codes. This research was supported by grants: NAZV No. 1357 and MSM 153100010.