Analysis of the relationship between alternative respiration and sterigmatocystin formation in Aspergillus nidulans

Ákos P. Molnár, Zoltán Németh, Erzsébet Fekete, Michel Flipphi, Nancy P. Keller, Levente Karaffa

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3 Citations (Scopus)

Abstract

Aspergillus nidulans has one gene for alternative oxidase (EC 1.10.3.11). To investigate the relationship between this mitochondrial terminal oxidase and the formation of the mycotoxin sterigmatocystin, the encoding aodA genewas both deleted and overexpressed. Relative to thewild-type, the cyanide-resistant fraction of respiration in the late stationary stage—when sterigmatocystin production occurs—doubled in the overexpressing mutant carrying three aodA gene copies, but decreased to 10% in the deletant. Essentially identical results were obtained regardless whether the cultures were illuminated or protected from light. In contrast, sterigmatocystin yield in the aodA deletant was about half of that in the control when grown in the dark, while aodA overexpression resulted in up to 70% more sterigmatocystin formed, the yield increasing with alternative oxidase activity. Results were quite different when cultures were illuminated: under those conditions, sterigmatocystin volumetric yields were considerably lower, and statistically unvarying, regardless of the presence, absence, or the copy number of aodA. We conclude that the copy number of aodA, and hence, the balance between alternative- and cytochrome C-mediated respiration, appears to correlate with sterigmatocystin production in A. nidulans, albeit only in the absence of light.

Original languageEnglish
Article number168
JournalToxins
Volume10
Issue number4
DOIs
Publication statusPublished - Apr 20 2018

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Keywords

  • Alternative oxidase
  • Aspergillus nidulans
  • Light regulation
  • Respiration
  • Sterigmatocystin

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis

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