Plant Pathology (2005) 54, 125-133

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A. Urbanietz and F. Dunemann (2005)
Isolation, identification and molecular characterization of physiological races of apple powdery mildew (Podosphaera leucotricha)
Plant Pathology 54 (2), 125-133
Abstract: The development of apple varieties displaying durable resistance against powdery mildew is one of the major aims in apple breeding programmes worldwide. For a reliable judgment of the resistance of different Malus genotypes, an extended knowledge about the virulence of the pathogen is necessary. To prove the existence of physiological races of Podosphaera leucotricha, 31 monoconidial isolates of the obligate biotrophic fungus representing five locations within Europe have been established and maintained over a period of 3-4 years. The isolates were maintained on in vitro shoots of the highly susceptible apple cv. Gibb's Golden Gage. An AFLP-based DNA fingerprinting protocol was developed and, using 54 stably reproducible AFLP markers, a dendrogram revealed genetic variability among different isolates of P. leucotricha. Although the molecular characterization of the isolates showed an overall low level of genetic variability, the high phenotypic diversity among European isolates suggest that sexual reproduction may also be involved in the disease cycle of the pathogen in Europe. Phytopathological tests using detached leaves of a collection of 36 Malus genotypes allowed the differentiation of five selected isolates by their virulence patterns. A high level of diversity in terms of virulence was obtained in P. leucotricha. From the present study, based on apple breeding germplasm, cultivars and Malus species, it can be concluded that physiological races of P. leucotricha do indeed exist in Europe.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Frank Dunemann

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
general biology - morphology - evolution


Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.


Podosphaera leucotricha Apple (Malus)