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

NICHEA M.J.; PROCTOR, ROBERT; PROBYN C.; PALACIOS S. A.; CENDOYA E.; SULYOK M; CHULZE S.N.; TORRES A.M.; RAMIREZ, M.L.

MYCOLOGIA.

ALLEN PRESS INC

Lugar: Lawrence; Año: 2022 vol. 114 p. 46 - 62

0027-5514

The Chaco wetland is formed by the floodplain of the Parana and Paraguay rivers and 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 of varied shapes. All the isolates also had identical, or nearly identical, partial sequences of TEF1 (translation elongation factor 1-α) and RPB2 (RNA polymerase second largest subunit), two genes used widely to distinguish Fusarium species from one another. But the sequences were distinct from reference sequences from F. armeniacum and Fusarium species closely related to it. In 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. Analysis of F. chaquense culture extracts revealed that this fungus can produce the trichothecenes T-2 and HT-2 toxin, neosolaniol, diacetoxyscirpenol, and monoacetoxyscirpenol, as well as the mycotoxin beauvericin and the pigment aurofusarin. Genome sequence analysis of three strains of this species 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.