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Genotypic diversity and mycotoxin production of fusarium graminearum isolates from wheat cultivated in Argentina

Cora Lilia Alvarez, Mariela Pamela Azcarate, Laura Terminiello, Daniel Cabral, Graciela Vaamonde, Virginia Fern�?�?�?�?�?�?�?¡ndez Pinto

Fusariumhead Blight(FHB) is an important disease affecting the production of wheat worldwide, that causes economic losses due to reduction in seed quality and presence of mycotoxins. The objective of the present work was to determine genotypic diversity and toxin production profile of Fusarium graminearumfromwheat cultivated in 19 districts ofBuenosAires province, Argentina.Vegetative Compatibility(VC) andMycelial Compatibility (MC) were used to study genotypic diversity. Fifty isolates of F. graminearum were studied, which formed 32 Mycelial Compatibility Groups (MCGs); in which 12 out of 32weremultimembers groups.Nitrate non utilizingmutants were obtained from34 isolates, that which ones analyzed byVC, formed 28 VegetativeCompatibilityGroups(VCGs)with 4multimembersVCGs.The variability indexwas 0.82 for VC and 0.64 forMC. Forty-four out of 50 isolates producedDeoxynivalenol(DON)(0.19 to 2169.3g g-1). The co-occurrence of DON- and Nivalenol(NIV) was detected in 27 isolates, with NIV levels between 0.1 and 14.3µg g-1. Simultaneous production of DON and both acetyl derivativeswere found in 27 isolates;DON,NIVand 15 acetylDONwere coproduced by 27 isolates, being these two the most frequent mycotoxin production profile. There was found that 41.67% of the multimember MCGs shared a similar toxin production profile. These results suggest a high diversity in the F.graminearum population from Argentinean wheat that should be taken into account to design better control strategies for FHB and suitable methods to analyse toxin contents in food and feed.