title: Distribution and diversity of natural product genes in marine and freshwater cyanobacterial cultures and genomes.
abstract: Natural products are a functionally diverse class of biochemically synthesized compounds, which include antibiotics, toxins, and siderophores. In this paper, we describe both the detection of natural product activities and the sequence identification of gene fragments from two molecular systems that have previously been implicated in natural product production, i.e., nonribosomal peptide synthetases (NRPSs) and modular polyketide synthases (PKSs), in diverse marine and freshwater cyanobacterial cultures. Using degenerate PCR and the sequencing of cloned products, we show that NRPSs and PKSs are common among the cyanobacteria tested. Our molecular data, when combined with genomic searches of finished and progressing cyanobacterial genomes, demonstrate that not all cyanobacteria contain NRPS and PKS genes and that the filamentous and heterocystous cyanobacteria are the richest sources of these genes and the most likely sources of novel natural products within the phylum. In addition to validating the use of degenerate primers for the identification of PKS and NRPS genes in cyanobacteria, this study also defines numerous gene fragments that will be useful as probes for future studies of the synthesis of natural products in cyanobacteria. Phylogenetic analyses of the cyanobacterial NRPS and PKS fragments sequenced in this study, as well as those from the cyanobacterial genome projects, demonstrate that there is remarkable diversity and likely novelty of these genes within the cyanobacteria. These results underscore the potential variety of novel products being produced by these ubiquitous organisms.
authors.affiliation: Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Ehrenreich
authors.forename: John B
authors.initials: JB
authors.lastname: Waterbury
authors.forename: Eric A
authors.initials: EA
authors.lastname: Webb
mesh_terms: D001685:Biological Factors / Q000378:metabolism*; D001688:Biological Products; D003470:Culture Media; D000458:Cyanobacteria / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D005618:Fresh Water / Q000382:microbiology; D014644:Genetic Variation; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D048630:Polyketide Synthases / Q000235:genetics* / Q000378:metabolism; D012623:Seawater / Q000382:microbiology
chemical_list: D001685:Biological Factors; D001688:Biological Products; D003470:Culture Media; D048630:Polyketide Synthases; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase