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. N.; SALIBIÁN, A.

REVISTA IBEROAMERICANA DE MICOLOGIA

ASOCIACION ESPANOLA MICOLOGIA-AEM

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

1130-1406

Background: Several fungal species represent a potential risk to embryos of Odontesthes bonariensis(Cuvier and Valenciennes, 1835), a euryhaline freshwater fish that lives in the Pampean inland watersand has potential economic relevance.Aims: To identify two fungi isolated from O. bonariensis eggs exposed to saline conditions and to characterizetheir pathogenicity and tolerance to sodium chloride solutions.Methods: The isolates were identified by morphological features, and a preliminar phylogenetic analysisusing sequences of translation elongation factor 1-alpha (EF-1) and calmodulin (CAM) was performed.Koch?s postulates were tested to identify the causative agent of fungal infection. The influence of NaCl onthe fungal growth was evaluated in in vitro assays.Results: The isolates LPSC 1001 and 1002 were identified as representatives of the genus Fusarium, andbelonging to the Fusarium incarnatum-Fusarium equiseti species complex (FIESC) and the Fusarium solanispecies complex (FSSC), respectively. Histological observations on eggs exposed in vitro to both isolatesin infectivity assays confirmed the ability of the fungal isolates to penetrate to egg?s chorionic membrane,leading to the death of embryos. Increasing NaCl concentration in the culture medium reduced the growthof the isolates LPSC 1001 and 1002, being completely inhibited at 160 and 120 g/l NaCl respectively.Conclusions: The isolates LPSC 1001 (FIESC) and 1002 (FSSC) were identified as fungal pathogens toO. bonariensis eggs. The use of NaCl solutions as antifungal treatment was not effective to control theinfection with these strains.