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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Toxicology & Mycotoxin Research » Research » Publications at this Location » Publication #332554
Research Project: Eliminating Fusarium Mycotoxin Contamination of Corn by Targeting Fungal Mechanisms and Adaptations Conferring Fitness in Corn and Toxicology and Toxinology Studies of Mycotoxins

Location: Toxicology & Mycotoxin Research

Title: A novel population of Fusarium fujikuroi isolated from southeastern U.S. winegrapes reveals the need to re-evaluate the species’ fumonisin production

Author
item BOLTON, STEPHANIE - University Of Georgia
item BRANNEN, PHILLIP - University Of Georgia
item Glenn, Anthony - Tony

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/23/2016
Publication Date: 8/31/2016
Citation: Bolton, S.L., Brannen, P.M., Glenn, A.E. 2016. A novel population of Fusarium fujikuroi isolated from southeastern U.S. winegrapes reveals the need to re-evaluate the species’ fumonisin production. Toxins 8:254; doi:10.3390/toxins809254.

Interpretive Summary: Mycotoxins pose a challenge to a safe food supply worldwide, and their threat is expected to worsen with climate change. Mycotoxin concerns in wine have focused mainly on ochratoxin A, but the discovery of fumonisin B2 in wine exemplifies the need for continued diligence. The wine industry in the southeastern United States has grown extensively, yet there has not been a detailed survey of the fungi associated with mature winegrapes in this region. To determine the mycotoxin risk in southeastern wine, grape samples were collected from vineyards during the 2013 harvest and potentially mycotoxigenic fungi were isolated from the samples. In total 314 Fusarium isolates were recovered, and most were identified as either Fusarium fujikuroi (239 isolates) or Fusarium proliferatum (52 isolates). These two species are particularly concerning since F. proliferatum is known to produce high concentrations of fumonisin B1, B2, and B3 mycotoxins, whereas F. fujikuroi is known to produce low concentrations of fumonisins. Assays were conducted to quantify fumonisin production for representative isolates, and surprisingly, nearly all F. fujikuroi isolates produced fumonisins B1, B2, and B3 at levels comparable to both the F. proliferatum isolates and the positive control, Fusarium verticillioides. Such capacity for fumonisin production provides evidence to reconsider F. fujikuroi as a mycotoxigenic threat to crops.

Technical Abstract: Mycotoxins pose a challenge to a safe food supply worldwide, and their threat is expected to worsen with our changing climate. The need for diligence is exemplified by the discovery of fumonisin B2 in wine, which joins ochratoxin A as a mycotoxin of concern in the grape-wine chain. To elucidate the mycotoxin risk in southeastern American wine, grape samples were collected from vineyards during harvest in 2013 and potentially mycotoxigenic fungi (Fusarium and Aspergillus) were isolated from the samples. Numerous Fusarium isolates were recovered and identified to the species level by comparison of translation elongation factor 1-a gene sequences to verified strains. Fusarium fujikuroi was the most abundant species recovered (239 isolates), followed by F. proliferatum (52), F. incarnatum-equiseti (14), F. oxysporum (7), F. concentricum (1), and F. solani (1). In vitro assays quantified fumonisin production for representative isolates via LC-MS/MS. Surprisingly, nearly all F. fujikuroi isolates produced fumonisins B1, B2, and B3 at levels comparable to both the F. proliferatum isolates and the positive control, Fusarium verticillioides. Such capacity for fumonisin production refutes the generally accepted notion that F. fujikuroi produces undetectable or low levels of fumonisins and provides evidence to reconsider this species as a mycotoxigenic threat to economically significant crops.