|O Donnell, Kerry|
Submitted to: Mycological International Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 8/17/2002
Publication Date: N/A
Technical Abstract: Fusarium head blight or scab of cereals is one of the most devastating plant diseases worldwide. These pathogens cause significant reduction in seed quality and yields and often contaminate seeds with trichothecene and estrogenic mycotoxins. Genealogical concordance phylogenetic species recognition was used to investigate species limits within this complex in order to understand the host range, geographic distribution and mycotoxin potential of these fusaria. Because trichothecene chemotypes are not well correlated with the species phylogeny, we investigated the evolutionary history of the trichothecene mycotoxin gene cluster. Results of these phylogenetic analyses demonstrated that polymorphism within these virulence-associated genes is trans-specific and appears to have been maintained by balancing selection acting on chemotype differences that originated in the ancestor of this important group of plant pathogens.