Location: Chemistry Research Unit
Title: Seed treatment with live or dead Fusarium verticillioides equivalently reduces the severity of subsequent stalk rot Authors
Submitted to: Journal of Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 6, 2013
Publication Date: September 1, 2013
Citation: Martins, V.F., Vaughan, M.M., Huffaker, A., Schmelz, E.A., Christensen, S.A., Sims, J.W., Benda, N.D., Swerbilow, J.C., Alborn, H.T., Teal, P.E. 2013. Seed treatment with live or dead Fusarium verticillioides equivalently reduces the severity of subsequent stalk rot. Journal of Phytopathology. 1-4. Interpretive Summary: Fusarium verticillioides is a deleterious fungal pathogen known for its negative agro-economic impact on maize production. While the effects of F.verticillioides pathogenicity are frequently associated with ear and stalk rot and the contamination of seed with carcinogenic mycotoxin, its positive impact as a beneficial endophyte is less recognized. Scientists at the USDA-ARS Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, have shown that application of live F.verticillioides to the maize seed enhances plants resistance to secondary stalk rot infection, and that application of dead fungus is also capable of providing an equivalent level of enhanced resistance. In response to stalk infection maize plants that received seed treatment with live or dead F.verticillioides accumulated terpenoid phytoalexins, defense metabolites, faster than control treated plants. This increase in defenses was associated with reduced fungal biomass at the later time point. Seed treatment did not pertinently activate plant defenses or reduce plant growth. These results suggest that seed treatment with dead F.verticillioides can be used as a “vaccination” method in order to decrease the severity of stalk rot and potentially pathogen infection throughout the plant.
Technical Abstract: Fusarium verticillioides is a widely distributed fungus that can associate with maize as a deleterious pathogen and an advantageous endophyte. Here, we show that seed treatment with live F.verticillioides enhances maize resistance to secondary stalk rot infection, and demonstrate that dead F.verticillioides is sufficient to provide an equivalent level of resistance. Seed treatment with live or dead F.verticillioides primes maize plants, and upon subsequent stalk infection, terpenoid phytoalexins accumulate faster than control treated plants and are subsequently associated with reduced fungal biomass at the later time point. Seed treatment did not constitutively activate plant defenses nor did it impact plant growth. These results suggest that seed treatment with dead F.verticillioides can be used as a “vaccination” method in or