Fusarium abutilonis and F. guadeloupense, two novel species in the Fusarium buharicum clade supported by multilocus molecular phylogenetic analyses

ABSTRACT

This study was conducted to elucidate evolutionary relationships and species diversity within the Fusarium buharicum species complex (FBSC). We also evaluate the potential of these species to produce mycotoxins and other bioactive secondary metabolites. Maximum likelihood and maximum parsimony analyses of sequences from portions of four marker loci (ITS rDNA, TEF1, RPB1, and RPB2) and the combined 4495 bp data set support recognition of seven genealogically exclusive species within the FBSC. Two of the three newly discovered species are formally described as F. abutilonis and F. guadeloupense based on concordance of gene genealogies and morphological data. Fusarium abutilonis induces leaf, stem, and root lesions on several weedy Malvaceae (Abution theophrasti, Anoda cristata, Sida spinosa) and a fabaceous host (Senna obtusifolia) in North America and also was recovered from soil in New Caledonia. Fusarium abutilonis, together with its unnamed sister, Fusarium sp. ex common marsh mallow (Hibiscus moscheutos) from Washington state, and F. buharicum pathogenic to cotton and kenaf in Russia and Iran, respectively, were strongly supported as a clade of malvaceous pathogens. The four other species of the FBSC are not known to be phytopathogenic; however, F. guadeloupense was isolated from human blood in Texas and soil in Guadeloupe. The former isolate is unique because it represents the only known case of a fusarial infection disseminated hematogenously by a species lacking microconidia and the only documented fusariosis caused by a member of the FBSC. Whole genome sequence data and extracts of cracked maize kernel cultures were analyzed to assess the potential of FBSC isolates to produce mycotoxins, pigments, and phytohormones.

KEYWORDS:

• Chlamydospores
• equisetin
• genealogical concordance phylogenetic species recognition (GCPSR)
• morphology
• RPB1
• RPB2
• sporodochial conidia
• TEF1
• whole genome sequence
• 2 new taxa

ACKNOWLEDGMENTS

The authors would like to thank Amy McGovern, Crystal Probyn, Ethan Roberts, and Deborah S. Shane for skilled assistance in various aspects of this study. T.G. and K.A.S. are grateful for contributions by Helgard I. Nirenberg in the early stages of this project. Thanks are due to the Canadian Collection of Fungal Cultures (DAOM, Ottawa) and the Institute for Epidemiology and Pathogen Diagnostics Culture Collection (Julius Kühn-Institute, Berlin) for providing cultures.

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DISCLOSURE STATEMENT

No potential conflict of interest was reported by the author(s).

SUPPLEMENTARY MATERIAL

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Additional information

Funding

This research was supported in part by the US Department of Agriculture, Agricultural Research Service National Program for Food Safety, National Science Foundation (NSF) grant DEB-1655980, Pennsylvania State Agricultural Experiment Station Project 4655, and CRTI project 04-0045RD. I.L. was supported in part by an appointment to the ARS Research Participation Program administered by the Oak Ridge Institute for Science and Education (ORISE) through an interagency agreement between the US Department of Energy (DOE) and the US Department of Agriculture (USDA). ORISE is managed by ORAU under DOE contract number DE-SC0014664. All opinions expressed in this paper are the authors’ and do not necessarily reflect the policies and views of USDA, DOE, or ORAU/ORISE.