title: Variability of the microcystin synthetase gene cluster in the genus Planktothrix (Oscillatoriales, Cyanobacteria).
abstract: In populations of Planktothrix, microcystin-producers and non-producers, which are morphologically identical, coexist. In order to develop a basis for the reliable detection of microcystin producers in field samples with polymerase chain reaction (PCR) based methods, we studied the presence and variability of eight regions of the mcy gene cluster in 46 Planktothrix strains, including both microcystin-producing and non-producing ones. PCR-amplification products for two mcy gene regions were also found in non-microcystin-producing strains, indicating the existence of natural mutants. PCR-products of the other regions studied were only detected in microcystin-producing strains. Two of these mcy-amplicons were variable in sequence and length. Four gene regions remained that were conserved and specific for microcystin-producing Planktothrix strains, and thus qualified to detect the respective chemotypes in environmental samples.
authors.affiliation: Department of Limnology of Stratified Lakes, Institute for Freshwater Ecology and Inland Fisheries, Alte Fischerhütte 2, 16775 Stechlin-Neuglobsow, Germany. susan.mbedi@igb-berlin.de
authors.forename: Susan
authors.initials: S
authors.lastname: Mbedi
authors.forename: Martin
authors.initials: M
authors.lastname: Welker
authors.forename: Jutta
authors.initials: J
authors.lastname: Fastner
authors.forename: Claudia
authors.initials: C
authors.lastname: Wiedner
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D000458:Cyanobacteria / Q000201:enzymology / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis; D023061:Gene Order; D005798:Genes, Bacterial; D014644:Genetic Variation; D052998:Microcystins; D008969:Molecular Sequence Data; D005810:Multigene Family; D010453:Peptide Synthases / Q000235:genetics*; D010456:Peptides, Cyclic / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D052998:Microcystins; D010456:Peptides, Cyclic; C078588:microcystin; D010453:Peptide Synthases