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Ontario Grain Farmer Magazine

Discovery and testing of corn silk associated probiotic microbes to combat Fusarium disease and mycotoxins: An exciting new frontier in an old battle

Principal Investigator: Manish Raizada

Research Institution: University of Guelph (U of G)

Timeline: April 2018 – March 2022

Objectives:

  • Culture silk-microbes from diverse corn varieties from across the Americas, test them in vitro for suppression of Fusarium (dual-culture), then test candidates in greenhouse trials (silk spraying), measuring disease and mycotoxins. If time and funding permit, perform greenhouse and/or seed storage trials with wheat for suppression of Fusarium Head Blight (FHB).
  • In parallel, since many microbes are non-culturable, determine the complete silk-microbe composition using culture-independent microbial DNA sequencing. Use anti-Fusarium genetic mapping populations (Lana Reid, AAFC-Ottawa) to determine whether partial corn resistance to Fusarium is partly mediated by promoting specific silk-microbes. Identify anti-Fusarium microbial DNA-profiles that could be selected directly by breeders.
  • Apply for field-release permits for field trials at Ridgetown and/or initiate licensing with a commercial partner for wider-scale trials.

Impacts:

  • The development of new commercial probiotic microbes that reduce silk-mediated Fusarium entry into corn kernels and hence reduce DON and other mycotoxins will benefit Ontario’s corn producers, processors, livestock and consumers.
  • The identification of a silk-associated microbial community profile that is associated with suppression of Fusarium graminearum and mycotoxins will benefit Ontario’s corn producers, processors, livestock and consumers.
  • Microbial profiles may be used directly for selection purposes during corn breeding.

Scientific Summary:

Similar to humans, plants are inhabited and coated by probiotic microbes. We demonstrated that plant cells, which are immobile, have maintained probiotics (endophytes) that are mobile to act similar to human immunity cells to seek-and-destroy pathogens, at pathogen-entry points. However, scientists have overlooked probiotics within pollen tubes (corn silks) – hollow channels that sperm use to fertilize eggs, resulting in grain. Fusarium pathogens also enter into grain using silk channels, creating mycotoxins that affect humans and livestock. In a preliminary experiment, we found diverse microbes within unexposed silks: Are some of these sentinels to combat pathogens?

We propose to culture fungicide-compatible silk-bacteria (tip/base) from diverse corn varieties from across the Americas, test them in vitro, then in greenhouse trials (silk spraying) to combat Fusarium and mycotoxins. In parallel, as many microbes are non-culturable, we will determine the complete probiotic composition of silks using culture-independent microbial DNA sequencing. We will use an anti-Fusarium genetic mapping population (AAFC-Ottawa) to determine whether partial corn resistance to Fusarium is in fact mediated by promoting specific silk microbes. We will identify anti-Fusarium microbial DNA-profiles that could be selected directly by breeders.

External Funding Partners:

Organic Federation of Canada (OSC)

Agriculture and Agri-Food Canada (AAFC)

Prairie Heritage Seeds

Alberta Wheat Commission

Saskatchewan Wheat Development Commission

In-kind contributors:

Martin Meinert

Dwayne Smith

Denis Brisebois