Podosphaera pannosa (syn. Sphaerotheca pannosa) on Rosa and Prunus spp.: Characterization of Pathotypes by Differential Plant Reactions and ITS Sequences

Authors

  • L. Leus,

    1. Authors’ addresses: 1Department for Plant Genetics and Breeding, CLO-DvP, Caritasstraat 21, 9090 Melle, Belgium; 2Department Crop Protection; 3Department Plant Production, Faculty of Bioscience Engineering, Gent University, Coupure links 653, 9000 Gent, Belgium; 4Department Biot, Hogeschool Gent, Voskenslaan 270, 9000 Gent, Belgium (correspondence to L. Leus. E-mail: leen.leus@hogent.be)
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  • 1,4 A. Dewitte,

    1. Authors’ addresses: 1Department for Plant Genetics and Breeding, CLO-DvP, Caritasstraat 21, 9090 Melle, Belgium; 2Department Crop Protection; 3Department Plant Production, Faculty of Bioscience Engineering, Gent University, Coupure links 653, 9000 Gent, Belgium; 4Department Biot, Hogeschool Gent, Voskenslaan 270, 9000 Gent, Belgium (correspondence to L. Leus. E-mail: leen.leus@hogent.be)
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  • 1,2 J. Van Huylenbroeck,

    1. Authors’ addresses: 1Department for Plant Genetics and Breeding, CLO-DvP, Caritasstraat 21, 9090 Melle, Belgium; 2Department Crop Protection; 3Department Plant Production, Faculty of Bioscience Engineering, Gent University, Coupure links 653, 9000 Gent, Belgium; 4Department Biot, Hogeschool Gent, Voskenslaan 270, 9000 Gent, Belgium (correspondence to L. Leus. E-mail: leen.leus@hogent.be)
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  • 1 N. Vanhoutte,

    1. Authors’ addresses: 1Department for Plant Genetics and Breeding, CLO-DvP, Caritasstraat 21, 9090 Melle, Belgium; 2Department Crop Protection; 3Department Plant Production, Faculty of Bioscience Engineering, Gent University, Coupure links 653, 9000 Gent, Belgium; 4Department Biot, Hogeschool Gent, Voskenslaan 270, 9000 Gent, Belgium (correspondence to L. Leus. E-mail: leen.leus@hogent.be)
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  • 1 E. Van Bockstaele,

    1. Authors’ addresses: 1Department for Plant Genetics and Breeding, CLO-DvP, Caritasstraat 21, 9090 Melle, Belgium; 2Department Crop Protection; 3Department Plant Production, Faculty of Bioscience Engineering, Gent University, Coupure links 653, 9000 Gent, Belgium; 4Department Biot, Hogeschool Gent, Voskenslaan 270, 9000 Gent, Belgium (correspondence to L. Leus. E-mail: leen.leus@hogent.be)
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  • and 1,3 M. Höfte 2

    1. Authors’ addresses: 1Department for Plant Genetics and Breeding, CLO-DvP, Caritasstraat 21, 9090 Melle, Belgium; 2Department Crop Protection; 3Department Plant Production, Faculty of Bioscience Engineering, Gent University, Coupure links 653, 9000 Gent, Belgium; 4Department Biot, Hogeschool Gent, Voskenslaan 270, 9000 Gent, Belgium (correspondence to L. Leus. E-mail: leen.leus@hogent.be)
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Department for Plant Genetics and Breeding, CLO-DvP, Melle, Belgium

Abstract

The powdery mildew fungus Podosphaera pannosa (Wallr.: Fr.) de Bary (syn. Sphaerotheca pannosa) is a major problem on roses worldwide. Twenty-six monoconidial isolates of Podosphaera collected on roses and Prunus spp. in Belgium, Germany, France, Denmark, Israel and The Netherlands were characterized on the basis of differential reactions on in vitro rose genotypes and Prunus avium L. and by DNA sequence analysis of the rDNA ITS (internal transcribed spacer) region. Twenty-four isolates were determined as P. pannosa. Amongst these, different groups could be distinguished. A first group of 18 isolates was highly virulent on rose and avirulent or very weakly virulent on P. avium. A second group of four isolates was highly virulent on both rose and P. avium. Analysis of the ITS sequence could discriminate these two groups of P. pannosa strains by a one base pair difference. Finally, two isolates of powdery mildew collected on Prunus sp. could be classified as P. pannosa based on their ITS sequence, which was identical to the ITS sequence of the isolates only highly virulent on roses. However, these two isolates were not able to infect roses. These results indicate that different strains of P. pannosa exist with varying host specificity. We demonstrated by ITS sequencing and plant reactions that the host range of P. pannosa comprises roses and Prunus spp.

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