Phylogenetic species, chemotypes and genotypes within Fusarium graminearum species complex isolates from soybean and maize stalk rot in Argentina

CHIOTTA M. L; BARROS G.G.; MARINELLI, A; CHULZE , S.N

Rotterdam

Congreso; The World Mycotoxin Forum IUPAC; 2012

ISM -IUPAC

Soybean, maize and wheat are the most important crops in Argentina. Members of the Fusarium graminearum species complex (FGSC) can infect these crops causing diseases such as Fusarium head blight in wheat, Gibberella ear and stalk rot in maize and root rot in soybean. These species can infected the grains which are often contaminated with B trichothecenes such as deoxynivalenol (DON), nivalenol (NIV) and its acetyl derivatives. Previous studies conducted in Argentina suggested that the differences in FGSC composition observed between wheat in center Argentina and the maize ear rot isolates collected from the Northwest area is indicative of a potential difference in host preference within the FGSC. However, there is little information about the FGSC composition in soybean crop. Recently, an increase prevalence of stalk rot caused by isolates belonging to FGSC was observed in the Center South region of Córdoba Province. According to these findings the aims of this work were: i) to characterize the phylogenetic species composition within the FGSC from soybean and maize stalk rot isolates; ii) to determine the genotype and chemotype from FGSC isolates using molecular and chemical analysis. The sequence analysis of the translation elongation factor 1α (TEF-1) gene, the trichothecene 3-O-acetyltransferase (TRI101) gene and putative reductase (RED) gene showed the presence of four species within the FGSC among the soybean isolates. These included F. graminearum, which was the predominant species and showed simultaneous production of DON/15-ADON (15-ADON genotype); F. meridionale and F. cortaderiae with simultaneous production of DON/NIV (genotype DON/NIV) and F. boothii with trichothecenes production similar to F. graminearum. Among the isolates collected from maize stalk rot, two phylogenetic species were characterized: F. graminearum and F. meridionale. In conclusion, the sequence analysis showed higher species diversity in soybean compare to maize and wheat and this study represents the first report to indicate that F. graminearum and F. meridionale may play a substantial role in maize stalk rot in Argentina.