Abstract
Zoosporangia form and size were studied on a collection of 94 strains of Plasmopara halstedii (sunflower downy mildew). Both oval and round forms were present in all strains analysed. The proportion of two forms varied significantly according to strain and plant age but more especially to host plant genotype. Whatever the strain or host genotype, oval zoosporangia were larger than round ones, but there was no relation between the proportion of the oval form and mean zoosporangia size. There was no relation between zoosporangia form or size and race virulence profiles or aggressiveness criteria, with the possible exception of zoosporangia size and sporulation density. It is concluded that, for this obligate parasite, although form and size of zoosporangia depend on pathogen strain, these characters also vary according to growth conditions of Plasmopara halstedii, in particular to the genotype of the plant host.
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References
Cohen Y, Sacksto WE (1973) Factors affecting infection of sunflower by Plasmopara halstedii. Can J Bot 51:15–22
Delanoë D (1972) Biologie et épidémiologie du mildiou du tournesol (Plasmopara helianthi Novot.). Inform Techn CETIOM 29:1–40
Delmotte F, Giresse X, Richard-Cervera S, M’Baya J, Vear F, Tourvieille J, Walser P, Tourvieille de Labrouhe D (2008) Single nucleotide polymorphisms reveal multiple introductions into France of Plasmopara halstedii, the plant pathogen causing sunflower downy mildew. Infect Genet Evol (in press)
De Wet J, Burgess T, Slippers B, Preisig O, Wingfield BD, Wingfield MJ (2003) Multiple gene genealogies and microsatellite markers reflect relationships between morphotypes of Sphaeropsis sapinea and distinguish a new species of Diplodia. Mycol Res 107:557–566
De Wet J, Wingfield MJ, Coutinho T, Wingfield BD (2002) Characterisation of the C morphotype of the pine pathogen Sphaeropsis sapinea. For Ecol Manage 161:181–188
Ghasolia RP, Asha S (2007) Morphological and pathogenic variability in rapeseed and mustard isolates of Sclerotinia sclerotiorum. Indian Phytopthol 60:76–81
Göker M, Voglmayr H, Riethmüller A, Oberwinkler F (2007) How do obligate parasite evolve? A multi-gene phylogenetic analysis of downy mildews. Fungal Gene Biol 44:105–122
Hall G (1989) CMI Descriptions of Pathogenic Fungi and Bacteria, Set 98, Nos. 971–980. Mycopathologia 106:183–211
Ioos R, Laugustin L, Rose S, Tourvieille J, Tourvieille de Labrouhe D (2007) Development of a PCR test to detect the downy mildew causal agent Plasmopara halstedii in sunflower seeds. Plant Pathol 56:209–218
Islam SZ, Badadoost M, Lambert KN, Ndeme A, Fouly HM (2004) Characterization of Phytophthora capsici isolates from processing pumpkin in Illinois. Plant Dis 89:191–197
Komjati H, Walcz I, Viranyi F, Zipper R, Thines M, Spring O (2007) Characterization of a Plasmopara angustiterminalis isolate from Xanhium strumarium. Eur J Plant Pathol 119:421–428
Nishimura M (1922) Studies in Plasmopara halstedii. I. The infection of Helianthus annuus L. by zoospores. J Coll Agric Hokkaido Imp Univ XL 3:185–216
Novotelnova NS (1966) Downy mildew in sunflower. Nauka, Moscow
Sakr N, Ducher M, Tourvieille J, Walser P, Tourvieille de Labrouhe D (2007) A new method to obtain monozoosporangial isolates of sunflower downy mildew (Plasmopara halstedii). Cryptogam Mycol 28:123–131
Seiler GJ, Gulya TJ (2000) Evaluation of wild sunflower species for downy mildew resistance. In Proceeding of the 13th International Sunflower Conference. Pisa, Italy, pp 1368–1374
Semal J, Fraselle J, Impens R, Kummert J, Lepoivre P, Meulemans M, Seilleur P, Vander veken J, Viseur J (1989) Traité de Pathologie Végétale. Les Presses Agronomiques de Gembloux, Belgium
Spring O, Thines M (2004) On the necessity of new characters for classification and systematics of biotrophic Peronosporomycetes. Planta 219:910–914
Spring O, Voglmayr H, Riethmüller A, Oberwinkler F (2003) Characterization of a Plasmopara isolate from Helianthus x laetiflorus based on cross infection, morphological, fatty acids and molecular phylogenetic data. Mycol Prog 2:163–170
Spring O, Bachofer M, Thines M, Riethmüller A, Göker M, Oberwinkler F (2006) Intraspecific relationship of Plasmopara halstedii isolates differing in pathogenicity and geographic origin based on ITS sequence data. Eur J Plant Pathol 114:309–315
Tourvieille de Labrouhe D, Pilorge E, Nicolas P, Vear F (2000) Le mildiou du tournesol. CETIOM, INRA Editions, France
Van der Plank JE (1968) Disease resistance in plants. Academic Press, New York
Vear F, Serre F, Roche S, Walser P, Tourvieille de Labrouhe D (2007) Recent research on downy mildew resistance useful for breeding industrial – use sunflowers. Helia 30:45–54
Acknowledgements
We would like to thank the Syrian Commission of Energy Atomic for a Doctoral Scholarship concerning the first author. This work was carried out with the financial support of the French Centre Technique Interprofessionnel des Oléagineux Métropolitains (CETIOM).
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Sakr, N., Ducher, M., Tourvieille, J. et al. Variation in form and size of Plasmopara halstedii (sunflower downy mildew) zoosporangia. Mycol Progress 7, 257–265 (2008). https://doi.org/10.1007/s11557-008-0568-y
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DOI: https://doi.org/10.1007/s11557-008-0568-y