Natural toxigenic fungal and mycotoxin occurrence in maize hybrids

Abstract

The objective of the present study was to investigate the susceptibility of maize hybrids to the natural occurrence of toxigenic fungal species, in particular toxigenic Aspergillus and Fusarium species, and mycotoxins (aflatoxin B1 (AFB1), deoxynivalenol (DON) and total fumonisins B1, B2 and B3 (FBs)). Grain samples of six commercial maize hybrids (MAS 34.B - FAO 300, MAS 40.F, MAS 48.L, KWS Konfites and ZP 427 - FAO 400, and MAS 56.A - FAO 500) were collected at harvest in 2018. A total of seven fungal genera, Acremonium, Alternaria, Epicoccum, Fusarium, Nigrospora, Penicillium and Rhizopus, were identified of which only species from the genus Fusarium were present on maize grains of all hybrids tested. The incidence of Fusarium spp. was higher in the hybrids MAS 48.L (54.6%), and MAS 56.A (53.3%), compared to MAS 40.F (37.3%), KWS Konfites (28%), MAS 34.B (22.6%) and ZP 427 (12%) hybrids. Among the identified Fusarium species (F. graminearum, F. proliferatum, F. subglutinans and F. verticillioides), F. proliferatum was present in all hybrids, ranging from 9.3% (ZP 427) to 30.7% (MAS 48.L ), whereas F. subglutinans was present in two hybrids, MAS 40.F (16%) and MAS 56.A (9.3%). The incidence of F. graminearum ranged from 0% (KWS Konfites) to 9.3% (MAS 34.B), while the incidence of F. verticillioides ranged from 0% (MAS 34.B and ZP 427) to 21.3% (MAS 48.L). In the samples, Aspergillus species were not identified. The effect of maize hybrids was significant on the level of mycotoxins. MAS 34.B hybrid had a statistically significantly higher levels of AFB1 and DON than other hybrids. The FBs level was the highest in the hybrid MAS 34.B (1202 mg kg-1 ) and the lowest in the hybrid KWS Konfites (88.33 mg kg-1 ). However, the FBs level did not differ between hybrids MAS 34.B, MAS 40.F, and MAS 56.L, MAS 40.F, MAS 48.L, and MAS 56.A, and KWS Konfites and ZP 427. In all hybrids, AFB1, DON, and FBs levels were below the maximum permissible levels stipulated by the legislation of the European Union and the Republic of Serbia in unprocessed maize. The agro-ecological conditions in 2018 favored the development of Fusarium species on maize grains of the hybrids tested, especially fumonisin producing species.

Cilj rada je bio da se ispita osetljivost razliĉitih hibrida kukuruza na prirodnu pojavu toksigenih vrsta gljiva, posebno toksigenih Aspergillus i Fusarium vrsta, i mikotoksina (aflatoksina B1 (AFB1), deoksinivalenola (DON) i ukupnih fumonizina B1, B2 i B3 (FBs)). Uzorci zrna šest komercijalnih hibrida kukuruza (MAS 34.B - FAO 300, MAS 40.F, MAS 48.L, KWS Konfites i ZP 427 - FAO 400 i i MAS 56.A - FAO 500) sakupljeni su u vreme berbe 2018. godine. Analizom mikobiota identifikovane su vrste iz sedam rodova, Acremonium, Alternaria, Epicoccum, Fusarium, Nigrospora, Penicillium i Rhizopus, od kojih su samo vrste iz roda Fusarium bile prisutne na zrnu kukuruza svih ispitivanih hibrida. Veća uĉestalost Fusarium spp. na zrnu kukuruza bila je kod hibrida MAS 48.L (54,6%) i MAS 56.A (53,3%) u poreĊenju sa hibridima MAS 40.F (37,3%), KWS Konfites (28%), MAS 34.B (22,6%) i ZP 427 (12%). MeĊu identifikovanim Fusarium vrstama (F. graminearum, F. proliferatum, F. subglutinans i F. verticillioides), vrsta F. proliferatum bila je prisutna kod svih ispitivanih hibrida u rangu od 9,3% (ZP 427) do 30,7% (MAS 48.L), dok je vrsta F. subglutinans bila prisutna kod dva hibrida MAS 40.F (16%) i MAS 56.A (9,3%). Uĉestalost F. graminearum je bila od 0% (KWS Konfites) do 9,3% (MAS 34.B), dok je uĉestalost F. verticillioides bila od 0% (MAS 34.B i ZP427) do 21,3% (MAS 48.L). U uzorcima zrna, Aspergillus vrste nisu bile identifikovane. Hibridi kukuruza statistiĉki su znaĉajno uticali na sadrţaj ispitivanih mikotoksina. Hibrid MAS 34.B imao je statistiĉki znaĉajno viši sadrţaj AFB1 i DON u odnosu na druge hibride. Sadrţaj FBs bio je najviši kod hibrida MAS 34.B (1202 mg kg-1 ), a najmanji kod hibrida KWS Konfites (88,33 mg kg-1 ). MeĊutim, sadrţaj FBs nije se razlikovao izmeĊu hibrida MAS 34.B, MAS 40.F i MAS 56.A, MAS 40.F, MAS 48.L i MAS 56.A i KWS Konfites i ZP 427. Kod svih ispitivanih hibrida, sadrţaji AFB1, DON i FBs bili su ispod maksimalno dozvoljenih koliĉina propisanih zakonskom regulativom Evropske Unije i Republike Srbije u nepreraĊenom kukuruzu. Agroekološki uslovi u 2018. godini pogodovali su razvoju Fusarium vrsta na zrnu kukuruza ispitivanih hibrida, i to posebno fumonizin producenata.