Submitted to: Mycological Society of America
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/2003
Publication Date: 7/31/2003
Citation: Geiser, D.M., Abbas, H.K., Desjardins, A.E., Hackett, M., Juba, J., O Donnell, K., Royse, J., Tunali, B. 2003. Phylogenetic and biological species boundaries around fusarium proliferatum. Mycological Society of America. Interpretive Summary:
Technical Abstract: Fusarium proliferatum (mating population D), F. fujikuroi (mating population C) and F. globosum are three closely related species in the Asian clade of the Gibberella fujikuroi species complex. Morphological analyses and mating tests do not always yield clear inferences for species identification in this group. To compare phylogenetic species boundaries with those defined by other means, portions of three loci, translation elongation factor 1-alpha (tef-1), beta-tubulin (benA) and the intergeneric spacer (IGS) region of the nuclear rRNA gene region, were sequenced in over 60 isolates previously identified as belonging to these species. The tef-1 and benA gene regions showed three clear clades corresponding to the species F. proliferatum, F. fujikuroi and F. globosum. The IGS sequences gave similar results, with three exceptions. Two isolates that had F. proliferatum-like tef-1 and benA alleles had F. fujikuroi-like IGS alleles, and one isolate with F. proliferatum-like tef-1 and benA alleles had a F. globosum-like IGS allele. This could be due to introgression, or to ancestral polymorphism. Two of these isolates were highly fertile in crosses with mating population D testers. Overall, F. proliferatum showed a surprisingly high degree of sequence polymorphism, and F. globosum comprised two distinct clades. These results showed good correspondence between species boundaries recognized using phylogenetic and other criteria, with some notable exceptions, underscoring the need for multiple loci in phylogenetic species recognition.