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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #161555
Title: MOLECULAR VARIABILITY OF SUNFLOWER DOWNY MILDEW, PLASMOPARA HALSTEDII, FROM DIFFERENT CONTINENTS

Author
item ROECKEL-DREVET, P - INRA, FRANCE
item TOURVIEILLE, J - INRA, FRANCE
item Gulya Jr, Thomas
item CHARMET, G - INRA, FRANCE
item NICOLAS, P - INRA, FRANCE
item TOURVIEILLE DE LABRO, D - INRA, FRANCE

Submitted to: Canadian Journal of Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/5/2003
Publication Date: 10/2/2003
Citation: ROECKEL-DREVET, P., TOURVIEILLE, J., GULYA JR, T.J., CHARMET, G., NICOLAS, P., TOURVIEILLE DE LABROUHE, D. MOLECULAR VARIABILITY OF SUNFLOWER DOWNY MILDEW, PLASMOPARA HALSTEDII, FROM DIFFERENT CONTINENTS. CANADIAN JOURNAL OF MICROBIOLOGY. 2003. V. 49. P. 492-502.

Interpretive Summary: Seventy-seven isolates of Plasmopara halstedii, the cause of sunflower downy mildew, were examined for RAPD polymorphisms with 21 primers. The isolates were from 12 countries in four continents, and this is the first study looking at the genetic diversity of this pathogen. None of the analysis revealed any consistent clustering of the isolates, nor were there patterns associated with race or geographic origin. The most differentiated races also had the lowest within-diversity indices, which suggest that they appreared recently with strong bottleneck effects. The results also suggest that fungal gene flow in can occur between countries.

Technical Abstract: The fungal pathogen causing sunflower downy mildew, Plasmopara halstedii, had not been studied using modern molecular genetic techniques. The USDA Sunflower Unit in Fargo, ND maintains a collection of downy mildew isolates dating back 20 years, representing both the US and more than a dozen other sunflower producing countries. A portion of these isolates were selected and given to a group of French university and government (INRA) researchers to investigate using the RAPD technique. While genetic diversity was substantial among the isolates, there were no clear patterns based on the geographic origin of the fungus, or on the 'race' of the fungus. The authors concluded that such relationships might be more evident if a large, more diverse collection of isolates were examined. Knowledge on the genetic diversity of this fungus, based on both conventional and molecular methods, will help scientists undertand the biology of this fungus and ultimately help in directing breeding efforts to produce sunflower hybrids with resistance to this international sunflower disease.