Toxigenic profile of Fusarium equiseti isolated from Argentinean soybean and pathogenicity on soybean seedlings

BARROS, G.G; ALANIZ ZANON, M.S; HAIDUKOUSKI, M; PASCALE, M; SCANDIANI, M.M; CHULZE, S.N

Mendoza

Congreso; Strategies to reduce the impact of mycotoxins in LatinAmerica in a global context; 2011

ISM, UNRC, Mycored

Fusarium equiseti represent the most abundant specie in the Fusarium complex isolated in Argentina from flowers, soybean pods and seeds. The aims of the present study were: (1) to assess the production of major type A and type B trichothecenes (diacetoxyscirpenol, neosolaniol, T-2 toxin and HT-2 toxin, nivalenol, deoxynivalenol)and zearalenone by 40 F. equiseti isolates on rice culture; (2) to evaluate the aggressiveness of two F. equiseti isolates in causing root rot of soybean seedlings under controlled conditions. Mycotoxins were determined by HPLC with fluorescence detection after derivatisation with 1-anthronylnitrile for type A trichothecenes (i.e. diacetoxyscirpenol, neosolaniol, T-2 toxin and HT-2 toxin), by HPLC with UV detection for type B trichothecenes (i.e. nivalenol and deoxynivalenol) and by TLC for zearalenone. Twenty-two out of 40 F. equiseti isolates produced diacetoxyscirpenol, nivalenol and ZEA alone or in combination, while none of the strains were able to produce deoxynivalenol, neosolaniol, T-2 toxin and HT-2 toxin.In relation to pathogenicity test, the inoculation of seedlings was performed using the method described by Xue et al. (2007).The results show thatboth F. equiseti strains testedwere unable todeveloprootrotsymptoms on soybean seedlings. The variableretentionintoxigenicity and the lowaggressiveness displayedby F. equiseti isolates suggests that this specie have asaprophyticlifestylein thesoybean agroecosystem in Argentina.