Deletion of the Δ12-oleic acid desaturase gene of a nonaflatoxigenic Aspergillus parasiticus field isolate affects conidiation and sclerotial development

Perng Kuang Chang, Richard A Wilson, N. P. Keller, T. E. Cleveland

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Aims: To investigate how linoleic acid affects conidial production and sclerotial development in a strictly mitotic Aspergillus parasiticus field isolate as related to improving biocompetitivity of atoxigenic Aspergillus species. Methods and Results: We disrupted A. parasiticus Δ12-oleic acid desaturase gene (odeA) responsible for the conversion of oleic acid to linoleic acid. We examined conidiation and sclerotial development of SRRC 2043 and three isogenic mutant strains deleted for the odeA gene (ΔodeA), either with or without supplementing linoleic acid, on one complex potato dextrose agar (PDA) medium and on two defined media: nitrate-containing Czapek agar (CZ) and Cove's ammonium medium (CVN). The ΔodeA mutants produced less conidia than the parental strain on all media. Linoleic acid supplementation (as sodium linoleate at 0.3 and 1.2 mg ml-1) restored the ΔodeA conidial production comparable to or exceeding the unsupplemented parental level, and the effect was medium dependent, with the highest increase on CVN and the least on PDA. SRRC 2043 and the ΔodeA mutants were unable to produce sclerotia on CVN. On unsupplemented PDA and CZ, ΔodeA sclerotial mass was comparable to that of SRRC 2043, but sclerotial number increased significantly to two- to threefold. Supplementing linoleic acid to media, in general, tended to decrease wild type and ΔodeA sclerotial mass and sclerotial number. Conclusions: Linoleic acid stimulates conidial production but has an inhibitory effect on sclerotial development. The relationship between the two processes in A. parasiticus is complex and affected by multiple factors, such as fatty acid composition and nitrogen source. Significance and Impact of Study: Conditions that promote sclerotial development differ from those required to promote maximum conidial production. Manipulation of content and availability of linoleic acid at different fungal growth phases might optimize conidial and sclerotial production hence increasing the efficacy of biocompetitive Aspergillus species.

Original languageEnglish (US)
Pages (from-to)1178-1184
Number of pages7
JournalJournal of Applied Microbiology
Volume97
Issue number6
DOIs
StatePublished - Dec 13 2004
Externally publishedYes

Fingerprint

Aspergillus parasiticus
Linoleic Acid
Aspergillus
Oleic Acid
oleic acid
linoleic acid
Genes
Agar
agar
genes
Solanum tuberosum
potatoes
mutants
glucose
Glucose
sclerotia
Fungal Spores
conidiation
conidia
microbial growth

Keywords

  • Aspergillus parasiticus
  • Biocompetition
  • Conidia
  • Linoleic acid
  • Sclerotia
  • Δ12-oleic acid desaturase gene

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology

Cite this

Deletion of the Δ12-oleic acid desaturase gene of a nonaflatoxigenic Aspergillus parasiticus field isolate affects conidiation and sclerotial development. / Chang, Perng Kuang; Wilson, Richard A; Keller, N. P.; Cleveland, T. E.

In: Journal of Applied Microbiology, Vol. 97, No. 6, 13.12.2004, p. 1178-1184.

Research output: Contribution to journalArticle

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abstract = "Aims: To investigate how linoleic acid affects conidial production and sclerotial development in a strictly mitotic Aspergillus parasiticus field isolate as related to improving biocompetitivity of atoxigenic Aspergillus species. Methods and Results: We disrupted A. parasiticus Δ12-oleic acid desaturase gene (odeA) responsible for the conversion of oleic acid to linoleic acid. We examined conidiation and sclerotial development of SRRC 2043 and three isogenic mutant strains deleted for the odeA gene (ΔodeA), either with or without supplementing linoleic acid, on one complex potato dextrose agar (PDA) medium and on two defined media: nitrate-containing Czapek agar (CZ) and Cove's ammonium medium (CVN). The ΔodeA mutants produced less conidia than the parental strain on all media. Linoleic acid supplementation (as sodium linoleate at 0.3 and 1.2 mg ml-1) restored the ΔodeA conidial production comparable to or exceeding the unsupplemented parental level, and the effect was medium dependent, with the highest increase on CVN and the least on PDA. SRRC 2043 and the ΔodeA mutants were unable to produce sclerotia on CVN. On unsupplemented PDA and CZ, ΔodeA sclerotial mass was comparable to that of SRRC 2043, but sclerotial number increased significantly to two- to threefold. Supplementing linoleic acid to media, in general, tended to decrease wild type and ΔodeA sclerotial mass and sclerotial number. Conclusions: Linoleic acid stimulates conidial production but has an inhibitory effect on sclerotial development. The relationship between the two processes in A. parasiticus is complex and affected by multiple factors, such as fatty acid composition and nitrogen source. Significance and Impact of Study: Conditions that promote sclerotial development differ from those required to promote maximum conidial production. Manipulation of content and availability of linoleic acid at different fungal growth phases might optimize conidial and sclerotial production hence increasing the efficacy of biocompetitive Aspergillus species.",
keywords = "Aspergillus parasiticus, Biocompetition, Conidia, Linoleic acid, Sclerotia, Δ12-oleic acid desaturase gene",
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T1 - Deletion of the Δ12-oleic acid desaturase gene of a nonaflatoxigenic Aspergillus parasiticus field isolate affects conidiation and sclerotial development

AU - Chang, Perng Kuang

AU - Wilson, Richard A

AU - Keller, N. P.

AU - Cleveland, T. E.

PY - 2004/12/13

Y1 - 2004/12/13

N2 - Aims: To investigate how linoleic acid affects conidial production and sclerotial development in a strictly mitotic Aspergillus parasiticus field isolate as related to improving biocompetitivity of atoxigenic Aspergillus species. Methods and Results: We disrupted A. parasiticus Δ12-oleic acid desaturase gene (odeA) responsible for the conversion of oleic acid to linoleic acid. We examined conidiation and sclerotial development of SRRC 2043 and three isogenic mutant strains deleted for the odeA gene (ΔodeA), either with or without supplementing linoleic acid, on one complex potato dextrose agar (PDA) medium and on two defined media: nitrate-containing Czapek agar (CZ) and Cove's ammonium medium (CVN). The ΔodeA mutants produced less conidia than the parental strain on all media. Linoleic acid supplementation (as sodium linoleate at 0.3 and 1.2 mg ml-1) restored the ΔodeA conidial production comparable to or exceeding the unsupplemented parental level, and the effect was medium dependent, with the highest increase on CVN and the least on PDA. SRRC 2043 and the ΔodeA mutants were unable to produce sclerotia on CVN. On unsupplemented PDA and CZ, ΔodeA sclerotial mass was comparable to that of SRRC 2043, but sclerotial number increased significantly to two- to threefold. Supplementing linoleic acid to media, in general, tended to decrease wild type and ΔodeA sclerotial mass and sclerotial number. Conclusions: Linoleic acid stimulates conidial production but has an inhibitory effect on sclerotial development. The relationship between the two processes in A. parasiticus is complex and affected by multiple factors, such as fatty acid composition and nitrogen source. Significance and Impact of Study: Conditions that promote sclerotial development differ from those required to promote maximum conidial production. Manipulation of content and availability of linoleic acid at different fungal growth phases might optimize conidial and sclerotial production hence increasing the efficacy of biocompetitive Aspergillus species.

AB - Aims: To investigate how linoleic acid affects conidial production and sclerotial development in a strictly mitotic Aspergillus parasiticus field isolate as related to improving biocompetitivity of atoxigenic Aspergillus species. Methods and Results: We disrupted A. parasiticus Δ12-oleic acid desaturase gene (odeA) responsible for the conversion of oleic acid to linoleic acid. We examined conidiation and sclerotial development of SRRC 2043 and three isogenic mutant strains deleted for the odeA gene (ΔodeA), either with or without supplementing linoleic acid, on one complex potato dextrose agar (PDA) medium and on two defined media: nitrate-containing Czapek agar (CZ) and Cove's ammonium medium (CVN). The ΔodeA mutants produced less conidia than the parental strain on all media. Linoleic acid supplementation (as sodium linoleate at 0.3 and 1.2 mg ml-1) restored the ΔodeA conidial production comparable to or exceeding the unsupplemented parental level, and the effect was medium dependent, with the highest increase on CVN and the least on PDA. SRRC 2043 and the ΔodeA mutants were unable to produce sclerotia on CVN. On unsupplemented PDA and CZ, ΔodeA sclerotial mass was comparable to that of SRRC 2043, but sclerotial number increased significantly to two- to threefold. Supplementing linoleic acid to media, in general, tended to decrease wild type and ΔodeA sclerotial mass and sclerotial number. Conclusions: Linoleic acid stimulates conidial production but has an inhibitory effect on sclerotial development. The relationship between the two processes in A. parasiticus is complex and affected by multiple factors, such as fatty acid composition and nitrogen source. Significance and Impact of Study: Conditions that promote sclerotial development differ from those required to promote maximum conidial production. Manipulation of content and availability of linoleic acid at different fungal growth phases might optimize conidial and sclerotial production hence increasing the efficacy of biocompetitive Aspergillus species.

KW - Aspergillus parasiticus

KW - Biocompetition

KW - Conidia

KW - Linoleic acid

KW - Sclerotia

KW - Δ12-oleic acid desaturase gene

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