Cyanobacteria – Gaining Benefit from Non-Axenic Cultures

PI: Dr. Silke Pradella

The oxygenic phototrophic Cyanobacteria are of outstanding biological importance in terms of their evolutionary history, diverse morphology (Fig. 1), physiology and capability to produce natural compounds. A few years ago, the Leibniz Institute DSMZ therefore expanded its portfolio to include Cyanobacteria in the collection of microorganisms. The DSMZ collection of Cyanobacteria currently comprises more than 900 strains from different habitats, representing approximately 100 genera. Many of these cyanobacterial strains have been classified based on morphological traits, as traditionally done, and their phylogenetic classification is pending.

    As primary producers Cyanobacteria are often engaged in close physical and physiological interactions with heterotrophic microorganisms in nature, like bacteria, fungi and protozoa (Fig. 2). For laboratory investigations, it is accordingly difficult to obtain pure, axenic cyanobacterial cultures. Most cyanobacterial strains in our collection are thus non-axenic (98%). For a comprehensive characterisation and phylogenetic classification of cyanobacterial strains and to explore the biological diversity of heterotrophs in non-axenic cyanobacterial cultures, a pilot project has been initiated: the microbiomes present in mixed cultures of Planktothrix, Phormidium, and Oculatella strains were analysed by metagenomic sequencing using the PacBio Sequel IIe technology available at the DSMZ. The complete genome sequence of the corresponding cyanobacterium was obtained in a single run from each of the cultures. In addition, up to five genomes of accompanying bacteria occurring in the cyanosphere were completely deciphered per cyanobacterial culture. The genome sequences of the cyanobacteria were analysed bioinformatically, resulting in the genome-based taxonomic assessment of the strains, the determination of their toxigenic potential and the elucidation of their axenity status. With the further implementation of this approach, Cyanobacteria of the DSMZ collection will contribute to an improvement of the cyanobacterial phylogeny and taxonomy. Furthermore, the DSMZ will provide the scientific community and their industrial partners with in-depth characterized cyanobacterial cultures.


    Selected references:

    1. Will, S.E., Henke, P., Boedeker, C., Huang, S., Brinkmann, H., Rohde, M., Jarek, M.,  Friedl, T., Seufert, S., Schumacher,M., Overmann, J., Neumann-Schaal, M. & Petersen, J. (2019) Day and night: metabolic profiles and evolutionary relationships of six axenic non-marine cyanobacteria. Genome biology and evolution 11.1: 270-294
    2. Marter, P.*, Huang, S.*, Brinkmann, H., Pradella, S., Jarek, M., Rohde, M., Bunk, B. and Petersen, J. (2021) Filling the Gaps in the Cyanobacterial Tree of Life—Metagenome Analysis of Stigonema ocellatum DSM 106950, Chlorogloea purpurea SAG 13.99 and Gomphosphaeria aponina DSM 107014. Genes 12: 389.
      * These authors contributed equally to this work.
    3. Koteska, D., Marter, P., Huang, S., Pradella, S., Petersen, J., & Schulz, S. (2022). Volatiles of the apicomplexan alga Chromera velia and associated bacteria. ChemBioChem. DOI: