The type I polyketides (PKs) and non-ribosomal peptides (NRPs) constitute one of the most diverse groups of natural products, and are common in bacteria and in fungi. The characterized metabolites often function as toxins against hosts and competitors, targeting various aspects of metabolism. In ascomycete fungi, most PKs and NRPs have been characterized from plant pathogens, in which they often serve as virulence factors needed for pathogenicity against their host plants, and from ecologically competitive saprobes such as Aspergillus flavus, with which they fend their food supplies against invaders. Surprisingly, Neurospora crassa contains at the least 7 PK synthases and 3 NRP synthetases, even though it is not known to make any secondary metabolites which function as toxins. In the eucaryotic model Dictyostelium, a diffusible signal molecule called DIF-1 induces the differentiation of prestalk-O cells. DIF-1 is a chlorinated alkyl phenone that is synthesized from a C12 polyketide precursor (Thompson CR and Kay RR., 2000). In bacteria, some compounds that are involved in toxins in higher concentration may act as a signalling compounds in low concentration. For example, it has recently been shown that aerial hyphae formation appears to be especially sensitive to inhibition by protein kinase inhibitors in Streptomyces (Waters et al., 2002). Our hypothesis is that polyketides and non-ribosomal peptides in Neurospora could play a role in a developmental aspect such as conidiation, hyphal fusion or mating.
Fungal Genet. Newsl. 50 (Supl):abstract
Full conference title:
22nd Fungal Genetics Conference
- Fungal Genetics Conference 22nd (2001)