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United States Department of Agriculture

Agricultural Research Service

Research Project: COMPARATIVE GENOMIC SYSTEMS FOR MOLECULAR DETECTION AND CONTROL OF TOXIGENIC FUSARIUM

Location: Bacterial Foodborne Pathogens & Mycology Research Unit

Title: Phylogenetically marking the limits of the genus Fusarium for post-Article 59 usage

Authors
item Geiser, David -
item ROONEY, ALEJANDRO
item Aoki, Takayuki -
item Kang, Seogchan -
item REHNER, STEPHEN
item O`DONNELL, KERRY

Submitted to: Mycological Society of America
Publication Type: Abstract Only
Publication Acceptance Date: July 18, 2012
Publication Date: July 18, 2012
Citation: Geiser, D.M., Rooney, A.P., Aoki, T., Kang, S., Rehner, S.A., O Donnell, K. 2012. Phylogenetically marking the limits of the genus Fusarium for post-Article 59 usage [abstract]. Mycological Society of America.

Technical Abstract: Fusarium (Hypocreales, Nectriaceae) is one of the most important and systematically challenging groups of mycotoxigenic, plant pathogenic, and human pathogenic fungi. We conducted maximum likelihood (ML), maximum parsimony (MP) and Bayesian (B) analyses on partial nucleotide sequences of genes encoding the largest (RPB1) and second largest (RPB2) RNA polymerase II subunits on 94 fusaria to infer phylogenetic relationships within the genus and 20 of its near relatives. Our analysis revealed that Cylindrocarpon spp. formed a basal monophyletic sister to a 'terminal Fusarium clade' (TFC sensu Gräfenhan et al. 2011), which comprised 20 strongly informally named clades. Inclusion of the basal most divergences within the TFC received strong support only from the Bayesian analysis (posterior probability (B-PP) = 0.99-1), with clades including F. ventricosum and F. dimerum forming the two earliest diverging lineages. An internode supporting the remaining TFC, however, was strongly supported by MP and ML boostrapping (ML-BS 100%, MP-BS 87%) and a B-PP of 1. This contrasts with the published analysis of a phylogeny based on RPB2 and acyl citrate lyase gene sequences, which did not yield significant support for this clade. Diversification time estimates were made to infer the origins of the genus and its clades. Because 1) the TFC includes all economically important fusaria, 2) virtually all of its members produce a recognizable Fusarium anamorph, 3) the Fusarium anamorph names are widely used compared to the associated teleomorphs; applied mycologists rarely if ever see the latter, and 4) it corresponds most closely to a fairly stable concept of the genus that has existed for nearly a century, herein we formally combine several teleomorph genera within the TFC and their types into Fusarium. The present study provides a robust framework to guide future comparative phylogenetic and phylogenomic analyses, including work to test and extend the hypotheses developed herein.

Last Modified: 9/29/2014
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