Genetic Regulation of Mycotoxin Biosynthesis

Abstract

Mycotoxin contamination in food poses health hazards to humans. Current methods of controlling mycotoxins still have limitations and more effective approaches are needed. During the past decades of years, variable environmental factors have been tested for their influence on mycotoxin production leading to elucidation of a complex regulatory network involved in mycotoxin biosynthesis. These regulators are putative targets for screening molecules that could inhibit mycotoxin synthesis. Here, we summarize the regulatory mechanisms of hierarchical regulators, including pathway-specific regulators, global regulators and epigenetic regulators, on the production of the most critical mycotoxins (aflatoxins, patulin, citrinin, trichothecenes and fumonisins). Future studies on regulation of mycotoxins will provide valuable knowledge for exploring novel methods to inhibit mycotoxin biosynthesis in a more efficient way.

Dual RNA-sequencing of Fusarium head blight resistance in winter wheat

“…GO enrichment of up-regulated gene sets showed significant enrichment of ABC-type transporters ( p = 7.9x10 -5 ) associated with DON export, isoprenoid biosynthesis ( p = 3.2x10 -2 ) and phosphopantetheine binding ( p = 2.4x10 -2 ) in F. graminearum from AC Emerson ( Figure 7A ). These enriched GO terms contained several up-regulated polyketide synthases belonging to the trichothecene cluster and DON biosynthesis pathway, including TRI5 and TRI6 which regulate and are necessary for DON biosynthesis ( Figures 8A, B )( Cuzick et al., 2008 ; Wang et al., 2023 ). Further, several terms associated with the ROS response were enriched in both F. graminearum from AC Morley and AC Emerson, including oxidoreductase activity ( p = 3.2x10 -12 ), tetrapyrrole binding ( p = 3.4x10 -3 ), antioxidant activity ( p = 2.1x10 -2 ) and response to oxidative stress ( p = 2.1x10 -2 ) ( Figure 7A ).…”

“…Trichothecene mycotoxins produced by Fusarium species have been demonstrated to increase pathogenicity in multiple hosts, acting through inhibition of protein synthesis and the generation of free radicals leading to oxidative stress ( Wu et al., 2017 ; Villafana et al., 2019 ). The C2H2 transcription factor TRI6 has been described as a positive regulator of trichothecene gene expression necessary for DON biosynthesis, with tri6 mutants demonstrating reduced expression of all TRI cluster genes, with the exception of TRI10 which is also hypothesized to be a positive regulator of TRI expression ( Wang et al., 2023 ). Further, TRI5 activity has also been described as essential for DON biosynthesis, with tri5 mutants not being able to produce DON and demonstrating significantly reduced pathogenicity ( Cuzick et al., 2008 ).…”

“…While several mycotoxins contribute to FHB virulence, the most influential and well-studied is the trichothecene mycotoxin DON. Prior studies have identified key regulators of DON biosynthesis within the trichothecene cluster, where tri5 and tri6 mutants were unable to produce DON, leading to reduced virulence and host colonization ( Audenaert et al., 2014 ; Wang et al., 2023 ). As DON plays a critical role in pathogenicity, DON detoxification has been identified in FHB-resistant species and cultivars, both through the activity of glutathione S-transferases like Fhb7 from Thinopyrum elongatum ( Guo et al., 2023 ; Wang et al., 2020 ), and through UDP-glycosyltransferase activity in Brachypodium distachyon , where DON is conjugated into deoxynivalenol-3-gluscoside ( Pasquet et al., 2016 ; Gatti et al., 2018 ; He et al., 2020 ).…”

A Chemically Defined Medium That Supports Mycotoxin Production by Stachybotrys chartarum Enabled Analysis of the Impact of Nitrogen and Carbon Sources on the Biosynthesis of Macrocyclic Trichothecenes and Stachybotrylactam

“…It is known, however, that the carbon source can have an impact on the production of mycotoxins, but the underlying mechanisms are unknown and most likely are not consistent in different fungal genera ( 82 ).…”

Genetic assessment of the effect of red yeast (Sporidiobolus pararoseus) as a feed additive on mycotoxin toxicity in laying hens

“…So far, various strategies have been developed to control mycotoxin contamination. They are classified into pre-harvest strategies to prevent mycotoxin production and post-harvest strategies to detoxify contaminated feed ( Agriopoulou et al, 2020 ; Wang et al, 2022 ). The pre-harvest strategies range from good agricultural practices to the use of biological control agents to prevent toxin production ( Luo et al, 2018 ; Agriopoulou et al, 2020 ; Caceres et al, 2020 ).…”