Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/10/2011
Publication Date: 9/10/2011
Citation: Aoki, T., Ward, T.J., Gale, L.R., O Donnell, K. 2011. Systematics, Phylogeny and Trichothecene Mycotoxin potential of Fusarium head blight cereal pathogens. Meeting Abstract.
Technical Abstract: Fusarium head blight (FHB) or scab of cereals is one of the most economically devastating plant diseases in the world today. Prior to 2000, the primary etiological agent of FHB was thought to comprise a single panmictic species, Fusarium graminearum. However, a series of studies we conducted over the past decade, employing genealogical concordance/discordance phylogenetic species recognition, have revealed this morphospecies comprises at least 16 phylogenetically distinct species (hereafter referred to as the F. graminearum species complex = FGSC). Moreover, many of these species exhibit significant biogeographic structure. By contrast, morphological species recognition has resolved only 6 species and 3 species groups within the FGSC, reflecting their morphological simplicity. Results of the multilocus molecular phylogeny, based on maximum parsimony and maximum likelihood analyses of 12 combined genes comprising 16.3 kb of aligned DNA sequence data, provide support for species radiations in Asia, North America, South America, Australia and/or Africa. These findings, together preliminary evidence of disjunct species in Asia and North America, suggest widespread allopatric speciation within the FGSC. A validated multilocus genotyping assay for species determination and trichothecene toxin chemotype prediction has been extraordinarily useful in the discovery of novel FGSC species represented in our global FHB surveys. Ongoing molecular and morphological analyses are being conducted to elucidate the full spectrum of FHB pathogens, their trichothecene toxin potential, and their movement resulting from the globalization of world trade.