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G‐protein signalling mediates differential production of toxic secondary metabolites
Author(s) -
Tag Andrew,
Hicks Julie,
Garifullina Gulnara,
Ake Charles,
Phillips T. D.,
Beremand Marian,
Keller Nancy
Publication year - 2000
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2000.02166.x
Subject(s) - biology , sterigmatocystin , aspergillus nidulans , mycotoxin , secondary metabolism , gliotoxin , gene , heterotrimeric g protein , gene expression , regulation of gene expression , microbiology and biotechnology , fungal protein , aspergillus , trichothecene , signal transduction , g protein , biochemistry , biosynthesis , aspergillus fumigatus , mutant
Filamentous fungi elaborate a complex array of secondary metabolites, including antibiotics and mycotoxins. As many of these compounds pose significant economic and health concerns, elucidation of the underlying cellular mechanisms that control their production is essential. Previous work revealed that synthesis of the carcinogenic mycotoxins sterigmatocystin (ST) and aflatoxin (AF) in Aspergillus species is negatively controlled by FadA, the α‐subunit of a heterotrimeric G‐protein. In sharp contrast, we show here that the dominant activating fadA allele, fadA G42R , stimulates transcription of a gene from the A. nidulans penicillin (PN) gene cluster and elevates penicillin production. Thus, FadA has opposite roles in regulating the biosynthesis of a potent antibiotic (PN) and a lethal mycotoxin (ST) in A. nidulans . Furthermore, expression of fadA G42R in Fusarium sporotrichioides increases trichothecene (TR) mycotoxin production and alters TR gene expression. Our findings reveal that a G‐protein defines an important control point for differential expression of fungal secondary metabolites within and across fungal genera. These data provide critical evidence suggesting that targeting G‐protein signal transduction pathways as a means of controlling or preventing the production of a single mycotoxin could have serious undesirable consequences with regard to the production of other secondary metabolites.