Chemotypes and genotypes characterization in Fusarium graminearum species complex isolated from soybean in Argentina

BARROS G.G.; ALANIZ-ZANON MARIA S; OVIEDO M.S; RAMIREZ M.L.; REYNOSO M.M.; TORRES A.M.; CHULZE , S.N

Merida

Congreso; Proceedings VI Latin American Congress of Mycotoxicology and II International Symposium on algal and fungal toxins for industry; 2010

Sociedad Latinoamericana de Micotoxicologia

Background: Fusarium rot of soybeans is described in the literature and different Fusarium species have been isolated from this commodity (Pitt and Hocking, 1997). These strains are known to produce a broad spectrum of toxins including trichothecenes of A- and B-types. Among B-type trichothecenes, deoxynivalenol (DON) and nivalenol (NIV) are important mycotoxins produced mainly by F. graminearum Schwabe [teleomorph = Gibberella zeae (Schwein.) Petch]. Strains of F. graminearum usually express one of three sets of trichothecene metabolites either: nivalenol and acetylated derivatives (NIV chemotype), (ii) deoxynivalenol and 3-acetyldeoxynivalenol (3-ADON chemotype), or deoxynivalenol and 15- acetyldeoxynivalenol (15-ADON chemotype) (Ward et al. 2002). Surprisingly, Fusarium isolates that produce both DON and NIV (NIV/DON chemotype) have been reported and described as “unknown” chemotypes (Ward et al. 2002; Quarta et al. 2006). Due to the toxicological differences between NIV and DON, it is important to survey the presence of different chemotypes in a given region and different crops. With the identification of the genes responsible for this toxin production, PCR has become increasingly popular to discriminate between different genotypes. More recently, primers pair based on derived form the Tri3, Tri5 and Tri7 genes of the trichothecene gene cluster were designed to differentiate between the three  genotypes. Aim: to characterized the chemotype and genotype diversity among the Fusarium graminearum species complex isolated from soybean.