Influence of a glyphosate-based herbicide on growth parameters and aflatoxin B1 production by Aspergillus section Flavi on maize grains

BENITO, NICOLÁS; MAGNOLI K.; CARRANZA C.S.; ALUFFI M.E.; MAGNOLI, C.E.; BARBERIS C.L.

REVISTA ARGENTINA DE MICROBIOLOGíA

ASOCIACION ARGENTINA MICROBIOLOGIA

Lugar: Buenos Aires; Año: 2021 vol. 53 p. 162 - 170

0325-7541

Glyphosate-based herbicides (GBH) are the main pesticides applied worldwide onmaize production. Glyphosate-resistant weeds led to the repeated application of high doses ofthe pesticide. In addition to environmental conditions, the presence of GBH affects the devel-opment of Aspergillus species and aflatoxin B1(AFB1) production under in vitro conditions. Theaim of this work was to evaluate the influence of a commercial GBH on growth and AFB1pro-duction by Aspergillus flavus and Aspergillus parasiticus strains under different water activity(aW) conditions. The following concentrations of active ingredient glyphosate were evaluated:20, 50, 200 and 500 mM. The lag phase prior to growth and growth rate did not change at 20and 50 mM (that is, at field recommended doses) at 0.98 and 0.95 aW; however, at increasingGBH concentrations, between 200 and 500 mM, the growth rate decreased at all aWconditions.In general, as the GBH concentration increased, AFB1production decreased. However, a signif-icant increase in toxin accumulation was found only at one of the aWconditions (0.95) at 21days with 50 mM of GBH in A. flavus and 20 and 50 mM of GBH in A. parasiticus. These resultsshow that, even though Aspergillus section Flavi growth did not increase, AFB1productionincreased on maize grains at GBH concentrations similar to those of field recommended dosesunder favorable water availability and temperature conditions.