Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Restriction fragment length polymorphisms and RAPD markers in DNA of Plasmopara halstedii, the downy mildew fungus of sunflower.

Abstract

Twenty-two P. halstedii isolates representing races 1, 3, 4, 5 and 6 from Hungary, Yugoslavia, Bulgaria, USA, France and Canada underwent molecular analysis. Southern hybridization of 44 clones with total DNA from each race identified 2 clones which distinguished the races when hybridized with BamHI digested total DNA. Hybridization with DNA from different isolates revealed identical patterns within races. Hybridization of clone 1-13B to EcoRI digested total DNA from each race produced fragments that differed by 0.75 kb, indicating the presence of a family of direct tandem repeats. RAPD analysis of isolates revealed extensive polymorphism and 2 random primers differentiated all isolates from each other. Two other primers identified RAPD markers for some race 3 isolates. RAPD patterns differed between a Bulgarian race 3 isolate and those from the USA, whereas they were similar for race 6 isolates from France and Canada. RAPD markers gave consistent patterns between different generations of one isolate.