Project 11: Growth and morphogenesis of Ulva mutabilis in a changing bacterial environment

This project is based at the Friedrich Schiller University Jena in Germany and its main objectives are to:

  1. Understand the molecular mechanisms by which symbiosis or antibiosis take place between the green macroalga Ulva mutabilis and associated bacteria;
  2. Examine the algal response to beneficial and algicidal bacteria in early stages of development; and
  3. Pilot the use of standardised Ulva germlings feed stocks with a synthetic microbiome as a tool to improve the sustainability of algal aquaculture in the long-term.

To achieve these objectives, the bacteria-driven metabolomic responses of U.mutabilis germlings is currently being correlated with algal development and morphogenesis (e.g. rhizoid and blade formation). Next, the tripartite community will be challenged with algicidal bacteria. These quadripartite communities allow us to study in detail how the tripartite system responds to specific changes in its environment, applying a combination of selected bacteria that are inoculated with axenic gametes of U. mutabilis, monitored by FISH in order to decipher the early stage responses of germination in this tripartite and quadripartite community.

The outcome of experiments will be compared with the dynamic metabolomic response of axenic macro and microalgae (Ectocarpus, Nannochloropsis) to their synthetic microbiome during secondments to CNRS (at Roscoff) and SAMS. Although CNRS and Jena already employ large-scale explorative approaches and powerful statistical analysis, this project is also benefiting from the expertise of colleagues at VIB for data integration. This project also has close links with Alga+ in Portugal as U.mutabilis was originally collected from the Portuguese coast.

Gianmaria Califano has been appointed researcher for this project. With the support of the above ALFF partners and insight into the molecular mechanisms of symbiosis or antibiosis between U.mutabilis and associated bacteria, Gianmaria is aiming to develop a defensive symbiosis model as a basis to engineer microbial community for macroalgal aquacultures.