Two Δ9-stearic acid desaturases are required for Aspergillus nidulans growth and development

Richard A Wilson, Perng Kuang Chang, Agnieszka Dobrzyn, James M. Ntambi, Robert Zarnowski, Nancy P. Keller

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Unsaturated fatty acids are important constituents of all cell membranes and are required for normal growth. In the filamentous fungus Aspergillus nidulans, unsaturated fatty acids and their derivatives also influence asexual (conidial) and sexual (ascospore) sporulation processes. To investigate the relationship between fatty acid metabolism and fungal development, we disrupted the A. nidulans sdeA and sdeB genes, both encoding Δ9-stearic acid desaturases responsible for the conversion of palmitic acid (16:0) and stearic acid (18:0) to palmitoleic acid (16:1) and oleic acid (18:1). The effects of sdeA deletion on development were profound, such that growth, conidial and ascospore production were all reduced at 22 and 37°C. Total fatty acid content was increased over 3-fold in the ΔsdeA strain, reflected in up-regulation of the expression of the fasA gene encoding the α chain of the fatty acid synthase, compared to wild type. Stearic acid accumulated approximately 3-fold compared to wild type in the ΔsdeA strain, while unsaturated fatty acid production was decreased. In contrast, disruption of sdeB reduced fungal growth and conidiation at 22°C, but did not affect these processes at 37°C compared to wild type. Interestingly, ascospore production was increased at 37°C for ΔsdeB compared to wild type. Total fatty acid content was not increased in this strain, although stearic acid accumulated 2-fold compared to wild type, and unsaturated fatty acid production was decreased. Combining the ΔsdeA and ΔsdeB alleles created a synthetic lethal strain requiring the addition of oleic acid to the medium for a modicum of growth. Taken together, our results suggest a role for sdeA in growth and development at all temperatures, while sdeB is involved in growth and development at lower temperatures.

Original languageEnglish (US)
Pages (from-to)501-509
Number of pages9
JournalFungal Genetics and Biology
Volume41
Issue number5
DOIs
StatePublished - May 1 2004

Fingerprint

Aspergillus nidulans
Unsaturated Fatty Acids
Growth and Development
Fatty Acids
Oleic Acid
Growth
Fatty Acid Synthases
Temperature
Palmitic Acid
Fungi
Up-Regulation
Alleles
Cell Membrane
Gene Expression
stearic acid
Genes

Keywords

  • Aspergillus nidulans
  • Fatty acid biosynthesis
  • Fungal development
  • Stearic acid
  • Δ9-Stearic acid desaturase

ASJC Scopus subject areas

  • Microbiology
  • Genetics

Cite this

Two Δ9-stearic acid desaturases are required for Aspergillus nidulans growth and development. / Wilson, Richard A; Chang, Perng Kuang; Dobrzyn, Agnieszka; Ntambi, James M.; Zarnowski, Robert; Keller, Nancy P.

In: Fungal Genetics and Biology, Vol. 41, No. 5, 01.05.2004, p. 501-509.

Research output: Contribution to journalArticle

Wilson, Richard A ; Chang, Perng Kuang ; Dobrzyn, Agnieszka ; Ntambi, James M. ; Zarnowski, Robert ; Keller, Nancy P. / Two Δ9-stearic acid desaturases are required for Aspergillus nidulans growth and development. In: Fungal Genetics and Biology. 2004 ; Vol. 41, No. 5. pp. 501-509.
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