Fusarium chaquense, sp. nov, a novel type A trichothecene–producing species from native grasses in a wetland ecosystem in Argentina

ABSTRACT

The Chaco wetland is among the most biologically diverse regions in Argentina. In collections of fungi from asymptomatic native grasses (Poaceae) from the wetlands, we identified isolates of Fusarium that were morphologically similar to F. armeniacum, but distinct from it by their production of abundant microconidia. All the isolates had identical, or nearly identical, partial sequences of TEF1 and RPB2. But they were distinct from reference sequences from F. armeniacum and Fusarium species closely related to it. Phylogenetic analysis of 34 full-length housekeeping gene sequences retrieved from whole genome sequences of three Chaco wetland isolates, 29 genes resolved the isolates as an exclusive clade within the F. sambucinum species complex. Based on results of the morphological and phylogenetic analysis, we concluded that the Chaco wetland isolates are a distinct and novel species, herein described as Fusarium chaquense, sp. nov., which is closely related to F. armeniacum. F. chaquense in culture can produce the trichothecenes T-2 and HT-2 toxin, neosolaniol, diacetoxyscirpenol, and monoacetoxyscirpenol, as well as beauvericin and the pigment aurofusarin. Genome sequence analysis also revealed the presence of three previously described loci required for trichothecene biosynthesis. This research represents the first study of Fusarium in a natural ecosystem in Argentina.

KEYWORDS:

• Beuvericin
• diacetoxyscirpenol
• Fusarium
• grasses
• HT-2 toxin
• monoacetoxyscirpenol
• neosolaniol
• RPB2
• T-2 toxin
• TEF1
• whole genome sequence
• 1 new taxon

ACKNOWLEDGMENTS

We thank Amy McGovern for her valuable technical assistance with generation and analysis of genome sequences.

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DISCLOSURE STATEMENT

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Additional information

Funding

M. J. Nichea is a fellow of CONICET and M. L. Ramirez, A. M. Torres, S. N. Chulze, S. A. Palacios, and E. Cendoya are members of the Research Career of CONICET. This work was supported by grants from Agencia Nacional de Promoción Científica y Tecnológica (MINCyT) through PICT-2019-2949-Prestamo BID and by the United States Department of Agriculture, Agriculture Research Service, Food Safety National Program 108, project number 5010-42000-050-00D.