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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 #368985

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: FVSTUA is a Key Regulator of Sporulation, Toxin Synthesis and Virulence in Fusarium verticillioides

item RATH, MANISHA - University Of Georgia
item Crenshaw, Nicole
item Lofton, Lily
item Glenn, Anthony - Tony
item Gold, Scott

Submitted to: Molecular Plant-Microbe Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2020
Publication Date: 6/2/2020
Citation: Rath, M., Crenshaw, N.J., Lofton, L., Glenn, A.E., Gold, S.E. 2020. FVSTUA is a Key Regulator of Sporulation, Toxin Synthesis and Virulence in Fusarium verticillioides. Molecular Plant-Microbe Interactions. 33:958-971.

Interpretive Summary: Mycotoxin production by fungi depends on developmental and genetic programing as well as environmental cues. We removed FvStuA, a gene encoding a conserved major fungal-development transcriptional regulator. We show that mutants produced highly reduced numbers of spores, dramatically reduced the production of fumonisin mycotoxins, and were less virulent on corn seedlings than the wild fungus. Fumonisin biosynthetic gene expression was also down in the FvstuA mutant, consistent with the fumonisin production result. This study indicates that FvStuA is involved in the regulation of mycotoxin production and virulence in Fusarium species, here important for fumonisin biosynthesis as it is for deoxynivalenol in Fusarium graminearum, another mycotoxin producing species.

Technical Abstract: Fusarium verticillioides is one of the most important pathogens of maize, causing rots and producing fumonisin mycotoxins during infection. Ingestion of fumonisin-contaminated corn causes underperformance and even fatal toxicity in livestock and is associated with neural tube birth defects, growth stunting in children and some cancers. StuA, an APSES class transcription factor, is a major developmental transcriptional regulator in fungi. It has been shown to regulate crucial developmental processes, such as sporulation, virulence and mycotoxin synthesis among others. In this study, the role of FvSTUA in F. verticillioides was examined by characterizing 'FvstuA deletion mutants functionally and transcriptomally. The deletion mutants exhibited slower vegetative growth, stunted aerial hyphae and significant reductions in microconidiation. Macroconidiation and hydrophobicity of the deletion strains were reduced as well. Additionally, fumonisin production and virulence of the deletion mutants were greatly reduced. Transcriptomic analysis revealed downregulation of expression of several genes in the fumonisin and fusarin C biosynthetic clusters and differential expression of genes involved in conidiation and virulence. Nuclear localization of FvSTUA supported its likely function as a transcription factor. Together, our results indicate that FvSTUA plays a global role in transcriptional regulation in F. verticillioides influencing morphogenesis, toxin production and virulence.