Location: Mycotoxin Prevention and Applied Microbiology Research
Project Number: 5010-42000-048-000-D
Project Type: In-House Appropriated
Start Date: Jan 19, 2016
End Date: Jan 4, 2021
Objective:
Objective 1: Identify and characterize microorganisms and microbial genes that can reduce trichothecene contamination of grain-based food and feed. Sub-objective 1.1: Determine the role of natural microbial populations in reducing Fusarium mycotoxins in wheat. Sub-objective 1.2: Identify trichothecene resistance mechanisms in a diversity of trichothecene-producing fungi. Objective 2: Determine the effects of climate change on susceptibility of wheat and corn to contamination by trichothecenes and other Fusarium mycotoxins. Sub-objective 2.1: Evaluate the effects of environmental conditions associated with climate change on susceptibility of wheat and corn to Fusarium infection and trichothecene contamination. Sub-objective 2.2: Identify stress-induced changes in plant metabolism and transcription associated with Fusarium infection and deoxynivalenol under projected future climate conditions. Objective 3: Determine the genomic diversity of Fusarium Head Blight pathogens and identify species or population-specific differences in host-pathogen interactions, mycotoxin production, or pathogen fitness under different climatic conditions. Sub-objective 3.1: Determine the genomic diversity and population affinities of NX-2 strains in relation to other FHB pathogens in North America, and utilize comparative genomics to identify regions of the genome influenced by adaptive evolution. Sub-objective 3.2: Characterize competitive interactions of Fusarium graminearum populations on spring and winter wheat. Sub-objective 3.3: Characterize changes in the aggressiveness and mycotoxin production of FHB species, chemotype groups, and populations in response to different climatic conditions.
Approach:
In recent years, the world has experienced an increase in mycotoxin contamination of grains due to climatic and agronomic changes that encourage fungal growth during cultivation. We will isolate and characterize major contributors (yeasts, filamentous fungi, and bacteria) to the microbial community associated with wheat cultivation. Microorganisms isolated from the wheat phyllosphere and rhizosphere will be evaluated both for their efficacy as biocontrol agents of mycotoxigenic Fusarium, and for their ability to detoxify or degrade mycotoxins. We will identify and characterize trichothecene detoxification genes from microbes capable of surviving mycotoxin exposure. As a parallel approach to trichothecene detoxification we will identify resistance mechanisms from diverse fungi that produce trichothecenes and have naturally developed strategies to cope with exposure to these toxins. Plants have evolved complex signaling mechanisms to respond to stress; however, simultaneous challenges by abiotic and biotic stress factors results in the activation of diverse signals that can have synergistic and antagonistic effects on each other. Additive abiotic stress can alter plant health and susceptibility to mycotoxins. We will evaluate the effects of environmental conditions associated with climate change on susceptibility of wheat and corn to Fusarium infection and trichothecene contamination and identify changes in plant physiology or defense that influence mycotoxin contamination. Climate induced physiological changes that occur in the host and influence mycotoxins and/or Fusarium infection will be useful as markers in plant breeding programs aimed at developing climate resilient fungal resistance strategies. Fusarium graminearum and other members of the F. graminearum species complex (FGSC) are the primary cause of Fusarium Head Blight (FHB) and trichothecene contamination of wheat worldwide. Understanding diversity at the level of species, genetic populations, and trichothecene chemotypes is critical to the development of effective disease control and mycotoxin reduction strategies. We will determine the extent, distribution, and significance of genomic diversity among FHB pathogen populations, species, and chemotype groups. Finally, we will test hypotheses regarding species, population, or chemotype-specific differences, in host-pathogen interactions, mycotoxin production, or pathogen fitness under different climatic conditions in order to understand the influence of host and climatic variables on pathogen composition and trichothecene contamination.
