Pathogenic ability and saline stress tolerance of two Fusarium isolates from Odontesthes bonariensis eggs

PACHECO-MARINO S.G., CABELLO M.N., DINOLFO M.I., STENGLEIN S.A., SAPARRAT M.C. & SALIBIÁN A.

REVISTA IBEROAMERICANA DE MICOLOGIA

ASOCIACION ESPANOLA MICOLOGIA-AEM

Lugar: Londres; Año: 2016 vol. 33 p. 13 - 20

1130-1406

Several fungal species may represent a substantial risk to embryos of Odontesthes bonariensis, an euryhaline freshwater fish that lives in the Pampean inland waters and has potential economic relevance. The present study reports the isolation and identification of two isolates: LPSC 1001 and LPSC 1002, from Odontesthes bonariensis eggs exposed to high salinity using morphological, molecular and phylogenetic approaches. The infective capacity and their tolerance to NaCl were evaluated in in vitro assays. The isolates were identified as representatives of Fusarium genus. A preliminar phylogenetic analysis using sequences of traslation elongation factor 1-alpha (EF- 1 alpha) and calmodulin (CAM) genes were conducted to resolve relationships among both isolates and other Fusarium species, this  analysis revealed that isolates LPSC 1001 and LPSC 1002 belong to Fusarium incarnatum-F. equiseti species complex (FIESC) and Fusarium solani species complex (FSSC) respectively. Pathogenicity assays confirmed infectivity of both isolates to Odontesthes bonariensis eggs, since histological observations showed fungal penetration to egg´s chorionic membrane, leading to the death embryos. Also, it was observed that increasing NaCl concentration in the culture medium progressively reduces the growth of both isolates, being completely inhibited at 160 and 120 g L-1 NaCl for the isolates LPSC 1001and 1002, respectively.