Impact of Fungi Co-occurrence on Mycotoxin Contamination in Maize During the Growing Season

Abstract

Maize is a possible host of many fungi, some of them able to produce different mycotoxins. Few studies exist on co-occurring fungi and resulting multi-mycotoxin contamination in field; for this reason, in field trials were conducted in two consecutive years to verify fungal incidence and mycotoxin production in the case of the co-occurrence of the three main mycotoxigenic fungi of maize in Italy: Aspergillus flavus, Fusarium verticillioides , and Fusarium graminearum able to produce, respectively, aflatoxin B1 (AFB1), fumonisins (FBs), and deoxynivalenol (DON). Artificial inoculation was done after silk emergence of maize and samples were collected with a 2 week schedule up to harvest time (four samplings). Fungal interaction resulted as playing a role for both fungal incidence and mycotoxins production, as did weather conditions too. Main interactions were noted between A. flavus and F. verticillioides , and between F. verticillioides and F. graminearum . In particular, as a result of fungal co-occurrence, AFB1 resulted stimulated by F. graminearum presence while no effects were noted in FBs and DON in case of F. verticillioides – F. graminearum co-occurrence. Interestingly, the co-presence of A. flavus significantly reduced both FB and DON production.

A Comprehensive Study on the Occurrence of Mycotoxins and Their Producing Fungi during the Maize Production Cycle in Spain

“…However, the stress on developing maize-particularly during reproductive phases-facilitates infection by the fungi, mycotoxin production and the contamination of the grain [32]. Moreover, it has been reported that, in the field, fungal metabolism changes in order to adapt to unfavorable environmental conditions or limited nutritional availability [33,34]. These authors highlighted the relevance of studies similar to those presented in this manuscript.…”

“…The presence of A. flavus was much more frequent and occurred at all stages; in comparison to the three Fusarium species detected, which were usually first detected at harvest. It is well-known that A. flavus and F. verticillioides usually co-occur in corn, since they are able to occupy different niches regarding carbon sources [34].…”

Potential Application of Lactic Acid Bacteria to Reduce Aflatoxin B1 and Fumonisin B1 Occurrence on Corn Kernels and Corn Ears

“…Aspergillus and Fusarium are the major fungal genera associated with corn contamination [10]. Indeed, many Aspergillus and Fusarium species are considered common contaminants of food and feed due to their ability to colonize and grow in a wide range of environmental conditions.…”

Natural toxigenic fungal and mycotoxin occurrence in maize hybrids

“…High temperatures and levels of humidity from silking to maturity stages are favourable conditions for fungal ear colonization by Fusarium species and synthesize of Fusarium mycotoxins (Logrieco et al, 2002), while drier growing seasons suitable for the growth of Aspergillus spp. and aflatoxin accumulation in maize crops (Giorni et al, 2019). The occurrence of mycotoxins in maize grains is also dependent on hybrid susceptibility (Blandino et al, 2017).…”