TRI Genotyping and Chemotyping: A Balance of Power

Abstract

Fusarium is among the top 10 most economically important plant pathogens in the world. Trichothecenes are the principal mycotoxins produced as secondary metabolites by select species of Fusarium and cause acute and chronic toxicity in animals and humans upon exposure either through consumption and/or contact. There are over 100 trichothecene metabolites and they can occur in a wide range of commodities that form food and feed products. This review discusses strategies to mitigate the risk of mycotoxin production and exposure by examining the Fusarium-trichothecene model. Fundamental to mitigation of risk is knowing the identity of the pathogen. As such, a comparison of current, recommended molecular approaches for sequence-based identification of Fusaria is presented, followed by an analysis of the rationale and methods of trichothecene (TRI) genotyping and chemotyping. This type of information confirms the source and nature of risk. While both are powerful tools for informing regulatory decisions, an assessment of the causes of incongruence between TRI genotyping and chemotyping data must be made. Reconciliation of this discordance will map the way forward in terms of optimization of molecular approaches, which includes data validation and sharing in the form of accessible repositories of genomic data and browsers for querying such data.

The Applicability of Species- and Trichothecene-Specific Primers in Monitoring the Fusarium graminearum Species Complex and Its Impact on the Surveillance of Fusarium Head Blight in Winter Wheat in Serbia

“…According to previous reports, Fusarium populations should be monitored at two levels: (1) the determination of changes in the diversity of Fusarium species in a given environment and (2) the detection of alterations in toxin production [37][38][39]. Since the relationship between the TRI genotype and chemotype can be incongruent, there are inconsistencies in the reports of their relationship and the applicability of methods for trichothecene chemotyping and genotyping [10]. Chemotype data were considered inappropriate for predicting the real risk of toxin production in field conditions due to their dependency on the in vitro induction of trichothecene production [10].…”

“…Since the relationship between the TRI genotype and chemotype can be incongruent, there are inconsistencies in the reports of their relationship and the applicability of methods for trichothecene chemotyping and genotyping [10]. Chemotype data were considered inappropriate for predicting the real risk of toxin production in field conditions due to their dependency on the in vitro induction of trichothecene production [10]. Trichothecene genotyping is the only approach that provides baseline data for the evaluation of mycotoxin risk and the confirmation of the presence of TRI genes in a given genome [40].…”

“…Identification of Fusarium spp. relies mostly on comparing multilocus sequence data using markers, which are usually the protein-coding genes of translation elongation factor 1 and/or the second largest subunit (RPB1 and/or RPB2) [10]. Some species-specific primers are more suitable for routine usage [10], but their validation in different regions is still needed.…”

“…relies mostly on comparing multilocus sequence data using markers, which are usually the protein-coding genes of translation elongation factor 1 and/or the second largest subunit (RPB1 and/or RPB2) [10]. Some species-specific primers are more suitable for routine usage [10], but their validation in different regions is still needed. To date, studies on the diversity of trichothecene genotypes in Serbia have been conducted only with isolates of F. graminearum s. stricto from a limited number of regions [11,12].…”

Fusarium culmorum Produces NX-2 Toxin Simultaneously with Deoxynivalenol and 3-Acetyl-Deoxynivalenol or Nivalenol

“…is encoded by TRI genes, comprising a core TRI cluster and one or two additional loci, depending on the species [ 13 ]. According to the dominant trichothecene produced, Fusarium strains producing trichothecenes B are partitioned into the 3-ADON chemotype, the 15-ADON chemotype, and the NIV chemotype [ 13 , 14 ].…”