Abstract
Strains of Sphaerotheca fuliginea, one of the causal agents of powdery mildew of cucurbits, were examined for differences in virulence, mating type and DNA polymorphism. The 28 strains were chosen to be diverse according to host and geographic origin. Characterization of virulence phenotypes was based on the expression of symptoms on 4 species of cucurbits and 6 cultivars of melon. Two pathotypes, capable of attacking either cucumber cv. ‘Marketer’ and melon cv. ‘IranH’ and squash cv. ‘Diamant’ or cucumber cv. ‘Marketer’ and melon cv. ‘IranH’ were observed. Tests on melon cultivars revealed 3 races. In tests of sexual compatibility with reference strains, heterothallism was observed for all isolates. Frequency of the two mating types differed significantly in the population. DNA polymorphism was determined both by restriction fragment length polymorphism (RFLP) of the ribosomal internal transcribed spacers (ITS) and 5.8S DNA amplified by the polymerase chain reaction and by random amplified polymorphic DNA (RAPD). For any one of the 11 restriction enzymes tested all strains presented an identical pattern of ITS RFLP. RAPD analysis, using 22 primers which provided reproducible patterns, revealed a relatively low degree of polymorphism. Furthermore, cluster analysis based on RAPD data (152 markers) did not separate groups within the species S. fuliginea. No association could be found between virulence, mating type, geographical and host origin and RAPD patterns. The lack of association between phenotypic and molecular markers and the close fit to linkage equilibrium for the characters examined suggest that recombination may play a role in populations of S. fuliginea.
Similar content being viewed by others
References
Bertrand F (1991) Les Oïdiums des Cucurbitacées: Maintien en culture pure, étude de leur variabilité et de la sensibilité chez le melon. Ph.D. thesis. University of Paris XI, Orsay, France
Chen X, L ine RF and Leung H (1993) Relationship between virulence and DNA polymorphism in Puccinia striiformis. Phytopathology 83: 1489–1497
Cohen R, L eibovich D, Shtienberg D and Paris HS (1993) Variability in the reaction of zucchini (Cucurbita pepo) to inoculation with Sphaerotheca fuliginea and methodology of breeding for resistance. Plant Pathol 42: 510–516
Délye C, Corio-Costet MF and Laigret F (1995) A RAPD assay for strain typing of the biotrophic grape powdery mildew fungus Uncinula necator using DNA extracted from the mycelium. Exp Mycol 19: 234–237
Epinat C, P itrat M and Bertrand F (1993) Genetic analysis of resistance of 5 melon lines to powdery mildews. Euphytica 65: 135–144
Hermansen JE, Torp U and Prahm LP (1978) Studies of transport of spores of cereal mildew and rust fungi across North sea. Grana 17: 41–46
Kenigsbuch Dand Cohen Y(1992) Inheritance and allelism of genes for resistance to races 1 and 2 of Sphaerotheca fuliginea in muskmelon. Plant Dis 76: 626–629
Kooistra E (1968) Powdery mildew resistance in cucumber. Euphytica 17: 236–244
McCreight JD, Pitrat M, Thomas CE, Kishaba AN and Bohn GW (1987) Powdery mildew resistance genes in muskmelon. J Amer Soc Hort Sci 112: 156–160
McDermott JM, M üller K and Wolfe MS (1993) Populations of powdery mildew of barley in Europe: a RAPD analysis of an old problem. In: Reynolds DR and Taylor JW (eds) The Fungal Holomorph: Mitotic, Meiotic and Pleomorphic Speciation in Fungal Systematics (pp 191–197) CAB International, Wallingford
McGrath MT (1994) Heterothallism in Sphaerotheca fuliginea. Mycologia 86: 517–523
McGrath MT, Staniszewska H and Shishkoff N (1996) Distribution of Mating types of Sphaerotheca fuliginea in the United States. Plant Dis 80: 1098–1102
Mohamed YF, Bardin M, Nicot PC and Pitrat M (1995) Causal agents of powdery mildew of cucurbits in Sudan. Plant Dis 79: 634–636
Möller EM, Bahnweg G, Sandermann H and Geiger HH (1992) A simple and efficient protocol for isolation of high molecular weight DNA from filamentous fungi, fruit bodies, and infected plant tissues Nucleic Acids Res 20: 6115–6116
Molot PM and Lecoq H (1986) Les oïdiums des cucurbitacées. I.-Données bibliographiques. Travaux préliminaires. Agronomie 6: 355–362
Mouyna I and Brygoo Y (1993) Les champignons et la PCR. In: Larzul D (ed) La PCR, un procédé de réplication in vitro (pp 335–341) Collection Génie Génétique, Tech. et Doc., Lavoisier, Paris
Nei M (1987) Molecular evolutionary genetics. Colombia, University Press, New York
Nei M and Lee WH(1979) Mathematical model for studying genetic variation in terms of restriction endonucleases. Proc Natl Acad Sci USA 76: 5269–5273
Ouellet T and Seifert KA (1993) Genetic characterization of Fusarium graminearum strains using RAPD and PCR amplification. Phytopathology 83: 1003–1007
Peever TL and Milgroom MG (1994) Genetic structure of Pyrenophora teres populations determined with random ampli-fied polymorphic DNA markers. Can J Bot 72: 915–923
Raymond M and Rousset F (1995a) GENEPOP (version 1.2): population genetics software for exact tests and ecumenicism. J Heredity 86: 248–249
Raymond M and Rousset F (1995b) An exact test for population differentiation. Evolution 49: 1280–1283
Rice WR (1989) Analysing tables of statistical tests. Evolution 43: 223–225
Sitterly WR (1978) Powdery mildews of Cucurbits. In: Spencer DM (ed) The Powdery Mildews (pp 360–379) Academic Press, London
Sokal RR and Sneath PHA (1963) Principle of numerical taxonomy. WH Freeman Co., San Fransisco
Sowell G Jr (1982) Population shift of Sphaerotheca fuliginea on muskmelon from race 2 to race 1 in the Southeastern United States. Plant Dis 66: 130–131
Sreenivasaprasad S, Brown AE and Mills PR (1993) Coffee berry disease pathogen in Africa: genetic structure and relationship to the group species Colletotrichum gloeosporioides. Mycol Res 97: 995–1000
Thomas CE (1978) A new biological race of powdery mildew of cantaloups. Plant Dis Rep 62: 223
Thomas CE, Kishaba AN, McCreight JD and Nugent PE (1984) The importance of monitoring races of powdery mildew on muskmelon. Cucurb Genet Coop Rep 7: 58–59
Vakalounakis DJ, Klironomou E and Papadakis A (1994) Species spectrum, host range and distribution of powdery mildews on Cucurbitaceae in Crete. Plant Pathol 43: 813–818
Van Der Vlugt-Bergmans CJB, Brandwagt BF, Van't Klooster JW, Wagemakers CAM and Van Kan JAL (1993) Genetic variation and segregation of DNA polymorphisms in Botrytis cinerea. Mycol Res 97: 1193–1200
Wolfe MS and McDermott JM (1994) Population genetics of plant pathogen interactions: the example of the Erysiphe graminis-Hordeum vulgare pathosystem. Annu Rev Phytopathol 32: 89–113
Yarwood CE (1978) History and taxonomy of powdery mildews. In: Spencer DM (ed) The Powdery Mildews (pp 1–37) Academic Press, London
Zar JH (1984) Biostatistical analysis. Prentice-Hall, Inc., Englewood Cliffs, New Jersey
Zijlstra S, Jansen RC and Groot SPC (1995) The relationship between powdery mildew (Sphaerotheca fuliginea) resistance and leaf chlorosis sensitivity in cucumber (Cucumis sativus) studied in single seed descent lines. Euphytica 81: 193–198
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bardin, M., Nicot, P., Normand, P. et al. Virulence variation and DNA polymorphism in Sphaerotheca fuliginea, causal agent of powdery mildew of cucurbits. European Journal of Plant Pathology 103, 545–554 (1997). https://doi.org/10.1023/A:1008608413984
Issue Date:
DOI: https://doi.org/10.1023/A:1008608413984