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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Toxicology & Mycotoxin Research » Research » Publications at this Location » Publication #337732

Research Project: Eliminating Fusarium Mycotoxin Contamination of Corn by Targeting Fungal Mechanisms and Adaptations Conferring Fitness in Corn and Toxicology and Toxinology Studies of Mycotoxins

Location: Toxicology & Mycotoxin Research

Title: Functional and molecular characterization of genes involved in antagonisms between two maize endophytes, Fusarium verticillioides and Sarocladium zeae

Author
item Gao, Minglu - University Of Georgia
item Gu, Xi - University Of Georgia
item Glenn, Anthony - Tony
item Gold, Scott

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/8/2016
Publication Date: 3/14/2017
Citation: Gao, M., Gu, X., Glenn, A.E., Gold, S.E. 2017. Functional and molecular characterization of genes involved in antagonisms between two maize endophytes, Fusarium verticillioides and Sarocladium zeae. Meeting Abstract. Meeting Book only.

Interpretive Summary: The mycotoxigenic fungus Fusarium verticillioides (Fv) is a prevalent seed-borne fungus of maize. A second fungus Sarocladium zeae (Sz) co-inhabits maize seed. Here we explore the effects on gene expression in Fv when it is exposed to the pyrrocidine antifungal products produced by Sz. Twenty seven Fv genes were found to be highly expressed in response to pyrrocidine. Mutants are being generated for these genes and their effects on pyrrocidine resistance and other functions are being analyzed and current results will be reported.

Technical Abstract: Fusarium verticillioides (Fv) is a prevalent seed-borne maize endophyte capable of causing severe kernel rot and fumonisin mycotoxin contamination. Within maize kernels, Fv is primarily confined to the pedicel, while another seed-borne fungal endophyte, Sarocladium zeae (Sz), is observed in embryos. In vitro assay has indicated that Sz was able to inhibit the growth of Fv. Two lactam-containing antibiotics by Sz, named pyrrocidine A (PA) and B (PB), are associated with antagonism of Fv by Sz. In order to explore the mechanism of antagonism, RNA-seq experiments were conducted by challenging the Fv liquid culture with PA and PB at subinhibitory concentrations to induce transcriptomic changes. A total of 27 genes with dramatic induction in both PA and PB treatments, including 17 genes encoding proteins with a beta-lactamase domain, were selected as targets to generate deletion mutants with our OSCAR protocol. Phenotypic and functional analyses of the mutants are being conducted to help us better understand the molecular mechanisms underlying the metabolic antagonism between these fungal endophytes. We will present current results on the bioinformatic analyses of RNA-seq experiments and functional characterization of the related mutants.