A naphthopyrone synthase-like PKS from Aspergillus terreus produces phytotoxins

Ref ID: 18292

Author:

Markus Gressler
, Christoph Zaehle
, Sabrina Boldt
, Christian Hertweck
and Matthias Brock

Author address:

Research Group Microbial
Biochemistry and Physiology;
Department of Biomolecular Chemistry, HKI Jena, Beutenbergstrasse 11A, 07745 Jena, Germany;

Full conference title:

Asperfest 9

Abstract:

Aspergillus terreus is a saprophytic filamentous fungus with its natural habitat in soil, compost or associated with decaying fruit. A.
terreus has a large potential to produce a wide variety of different secondary metabolites. However, it lacks a polyketide synthase
(PKS) gene conserved in all related Aspergillus species that produces a naphthopyrone derivative responsible for colouration of
conidia. Here, we discovered that in A. terreus the PKS most closely related to naphthopyrone synthases produces a phytotoxin.
Analysis of HPLC profiles from a PKS deletion mutant revealed that it is required for the synthesis of at least 15 different metabolites,
among them the major metabolite terrein. This well-known phytotoxin is a strong antioxidant that shows weak toxicity to mammalian
cells but potently harms the surface of several fruits. Using a beta- galactosidase reporter strain we observed a weak expression of the
gene cluster on minimal media and moderate activation on complex media. Interestingly, expression strongly increased in presence of
plant derived compounds such as malt extract or different fruit juices. This indicates a specific recognition of yet unknown plant
compounds resulting in phytotoxin production. Further analyses of the gene cluster and its metabolites are under investigation.

Abstract Number: 42)

Conference Year: 2012

Link to conference website: NULL

New link: NULL

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