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Biological control of Fusarium disease in corn and wheat using endophytes as seed treatments

Biological control of Fusarium disease in corn and wheat using endophytes as seed treatments

Principal Investigator: Manish Raizada

Research Institution: University of Guelph

Timeline: May 2014 – April 2018

Objectives:

  • Evaluate in greenhouse tests the efficacy of endophytes to control Fusarium disease in Fusarium-inoculated corn and wheat when endophytes are applied as seed coatings or onto ears at silking stage.
  • Evaluate in field tests the efficacy of endophytes (identified in greenhouse tests) to control Fusarium disease and mycotoxin development on Fusarium-inoculated corn hybrids that are susceptible and moderately resistant to Fusarium.
  • Investigate the anti-Fusarium mode(s) of action in the endophyte candidates that are effective at controlling Fusarium disease and mycotoxin development in field tests.

Impacts:

  • The development of probiotic sprays for corn and wheat may lead to commercially available biological controls for combating the pathogen of Ontario corn and wheat called Fusarium graminearum, which creates a toxin called deoxynivalenol (DON) that negatively affects humans and livestock.

Scientific Summary:

Fusarium graminearum and its sexual stage, Gibberella zeae, cause tough-to-control diseases in many cereals, including Fusarium head blight (FHB) in wheat and Gibberella ear rot (GER) in corn. These costly diseases reduce grain yield, grade and quality, and can produce mycotoxins, such as deoxynivalenol (DON), that limit the grain’s end-use. Recent FHB epidemics caused losses of $200-million to Ontario’s winter wheat farmers, while 23% of corn in Ontario in 2011 had detectable DON levels. Thus far, there has been limited success with crop breeding for resistance, and fungicide sprays have been shown to be only partially effective. Major biotech companies are now investing billions of dollars into biologicals, naturally occurring probiotics from plants that can be coated onto crop seeds, to suppress diseases and pests.

The overall objective of this 3-year GFO proposal was to develop effective biological control against either Gibberella ear rot (GER) or Fusarium head blight (FHB) in wheat based on coating seeds or field spraying with beneficial microbial endophytes isolated from corn and finger millet. This project has resulted in the identification of 5 anti-Fusarium bacterial strains, 4 anti-Fusarium fungal strains, several microbial anti-Fusarium genes, and at least 7 bio-fungicides that suppress Fusarium graminearum in vitro and/or in BOTH corn and wheat. All of the 5 bacterial endophytes were discovered to dramatically suppress mycotoxin DON accumulation in replicated greenhouse trials in corn (up to 97%) and wheat (up to 85%). Replicated field trials with corn showed that 3 bacterial endophytes hold promise, with one endophyte, in particular, reducing DON mycotoxin accumulation by up to 65%. Year to year inconsistencies were observed in the efficacy of the endophytes. Nevertheless, the endophytes appear to be the most successful biocontrol agents against F. graminearum reported in the scientific literature.

Silk spraying of the endophytes was shown to be more effective than seed-coating. The bacterial endophytes are likely compatible with fungicides, and hence may permit integrated disease management. All the endophyte strains have been licensed to the private sector to permit formulation improvements and multi-site, multi-variety testing. This project has garnered global interest by scientific colleagues (speaker invitations to Berkeley, John Innes Centre, etc.), led to 11 scientific publications, one U.S. patent and one licensing agreement, one PhD thesis, one MSc thesis (in progress), a nomination for the best young scientist in Ontario (Polanyi Prize to PhD student Walaa Mousa), received attention from grower media outlets (e.g., two articles in Top Crop Manager magazine), was featured internationally on CBC Radio Quirks and Quarks, and has catalyzed future new approaches and grants to combat Fusarium in both corn and wheat.

External Funding Partners:

NSERC-CRD (Natural Sciences and Engineering Research Council of Canada’s Collaborative Research and Development program)

Project Related Publications:

Mousa, W.K., Shearer, C. Limay-Rios V, Khalaf E, Shehata HR, Zhou T, and Raizada, M.N.  2022. Bacterial endophytes form wild and ancient maize suppress Fusarium head blight in wheat and inhibit mycotoxin accumulation (in revision).

Mousa WK, Shearer C, Limay-Rios V, Ettinger CL, Eisen JA, Raizada, M.N. 2016b. Root hair-endophyte stacking (RHESt) in finger millet creates a physico-chemical barrier to trap the fungal pathogen Fusarium graminearum. Nature Microbiology 1: 16167.

Mousa WK, Schwan, A. and Raizada, M.N. 2016a. Characterization of antifungal natural products isolated from endophytic fungi of finger millet (Eleusine coracana). Molecules 21: 1171.

Mousa, W.K. and Raizada, M.N. 2016. Natural Disease Control in Cereal Grains. In: C. Wrigley, H. Corke, K. Seetharam, Faubion, J. (eds) Encyclopedia of Food Grains. 2nd Edition. Oxford: Academic Press, pp. 257-263.

Mousa, W.K., Shearer, C Limay-Rios V., Zhou, T., and Raizada, M.N. 2015a. Bacterial endophytes from wild maize suppress Fusarium graminearum in modern maize and inhibit mycotoxin accumulation. Frontiers in Plant Science 6, 805.

Mousa, W.K., Schwan, A., Davidson, J, Strange, P., Liu, H., Zhou, T., Auzanneau, F-I., and Raizada, M.N. 2015b. An endophytic fungus isolated from finger millet (Eleusine coracana) produces anti-fungal natural products. Frontiers in Microbiology 6, 1157.

Mousa, W.K. and Raizada, M.N. 2015. Biodiversity of genes encoding anti-microbial traits within plant associated microbes. Frontiers in Plant Science 6, 231.  (review)

Ettinger, C.L., Mousa, W.K., Raizada, M.N., Eisen, J.A. 2015. Draft Genome Sequence of Enterobacter sp. Strain UCD-UG_FMILLET (Phylum Proteobacteria). Genome Announcements 3: e01461-14.

Johnston-Monje, D., Mousa, W.K., Lazarovits, G., Raizada, M. N. 2014.

Impact of swapping soils on the endophytic bacterial communities of pre-domesticated, ancient and modern maize. BMC Plant Biology, 14:233.

Mousa, W. K., Raizada, M. N. 2013. The diversity of anti-microbial secondary metabolites produced by fungal endophytes: An interdisciplinary perspective. Frontiers in Microbiology, 4, 65.