Production of mycotoxins by Fusarium graminearum isolated from small cereals (wheat, triticale and barley) affected with scab disease in Southern Brazil

Abstract

Fusarium fungi are known to be pathogenic for plants and mycotoxin producers. The in vitro production of deoxynivalenol and zearalenone was qualitatively evaluated in 24 different isolates of Fusarium graminearum collected from small cereals associated with the scab disease, in southern Brazil. Isolates were cultivated in rice during 14 days at 28ºC. Cultivates were extracted with methanol:water (40:60 v/v) and analyzed by thin layer chromatography. Other trichothecenes (diacetoxyscirpenol, fusarenon-X, neosolaniol and nivalenol) and zearalenol, often produced by Fusarium, were also analyzed. In the conditions used, it was possible to detect zearalenone and deoxynivalenol in 67% and 33% of the isolates, respectively. The presence of zearalenol, diacetoxyscirpenol and fusarenone was also detected. None of the isolates was found to produce nivalenol or neosolaniol.

Optimization of culture conditions of Fusarium solani for the production of neoN-methylsansalvamide

“…fusaproliferin, enniatins, and beauvericin) from Fusarium strains has been shown to be 20-30°C. 20,22,23,[26][27][28] Consistent with these data, results from this study indicate that an optimum temperature for the maximal production of neoN-methylsansalvamide was about 25°C.…”

“…After cooling, cereals were inoculated with spores of F. solani KCCM90040 (approximately 10 5 spores) then culture was cultivated at 25°C and the level of neoN-methylsansalvamide was measured at 1, 2, 3, and 4 weeks. The culture was extracted with acetonitrile : methanol : water = 16 : 3 : 1 (v/v/v), 22) and the extract was defatted twice with 25 mL of n-heptane. After the bottom layer was evaporated to dryness, the residue was dissolved in 50 mL of methanol : water = 55 : 45 (v/v) and extracted twice with 25 mL of dichloromethane (CH 2 Cl 2 ).…”

“…21) In general, efficiency of secondary metabolite production from fungus is influenced by multiple parameters such as temperature, growth time, nutrition; their effects may be either independent or interactive. 22) Therefore, the production of neoN-methylsansalvamide can be effected by environmental conditions. In our preliminary study, F. solani KCCM90040 produced neoN-methylsansalvamide only on solid culture media of cereals, and the optimal culture conditions for production of this cyclic pentadepsipeptide have not yet been studied.…”

“…23,24) For F. subglutinans ITEM-1434, the highest amount of beauvericin was produced on rice at 25°C. 22) Generally, the optimum temperature for producing various secondary metabolites (e.g. fusaproliferin, enniatins, and beauvericin) from Fusarium strains has been shown to be 20-30°C.…”

Survey of mycotoxins in Southern Brazilian wheat and evaluation of immunoassay methods

“…Although ZEA is an important mycotoxin produced by members of the FGSC, few studies report its occurrence in Brazilian wheat Tibola et al, 2016). It is known that ZEA co-occur with DON especially when produced by FGSC isolates (Tangni et al, 2010), which is indeed the main pathogen in Brazil and a known ZEA producer (Geraldo et al, 2006). The ZEA levels found in our study are similar to those reported in previous studies on commercial wheat from Brazil (RS, 70.9 µg kg −1 and PR, 57.9 µg kg −1 ) (Tralamazza et al, 2016).…”