Project 2: Bacteria as adverse modulators of signal molecules from benthic diatoms

This project examines the cross-kingdom effects of bacteria on diatom signalling. A growing number of studies show that lytic bacteria are capable of directly interfering with diatom growth and propagation. In this project we will examine how bacteria exploit the pheromone chemistry of the algae to support pathogenicity, and how the alga reacts to and adapts its pheromone chemistry to the presence of these bacteria.

Based in the Faculty for Chemistry and Earth Sciences at the Friedrich Schiller University Jena, project 2 is located in the core discipline of bio-organic and analytical chemistry, whilst including aspects of microbiology and algal physiology. Established in 1558, the Friedrich Schiller University Jena is one of the oldest universities in Germany.

A growing number of studies show that lytic bacteria are capable of directly interfering with diatom growth and propagation. We recently identified that other more subtle mechanisms of bacteria-diatom interactions may also influence the propagation of these algae. Diatoms, such as the benthic pennate species Seminavis robusta, rely on pheromones to mediate synchronization of sexuality as well as mate-finding. We found the first diatom pheromone as a cyclic diproline that mediates attraction of a compatible mating type. This pheromone, however, offers benthic bacteria the means to interfere with signalling by, for example, metabolism or uptake of diatom borne signals. An active signal transformation might limit the availability of the pheromone to mating partners (based on unpublished results).

In this project we will examine how bacteria exploit the pheromone chemistry of the algae to support pathogenicity and how the alga reacts and adapts its pheromone chemistry to the presence of these bacteria.

Emilio Cirri has been appointed researcher for project 2. As part of his research at Jena, Emilio performs target analytics of the diatom pheromones, as well as following an exo-metabolomics approach to monitor community relevant molecules within the cross kingdom interaction. In close collaboration with the University of Ghent, he will follow the response of the alga to bacterial challenges using transcriptomics techniques. The metabolomics and transcriptomics data sets will be combined to deliver a comprehensive picture of signalling events in cross kingdom interactions. In collaboration with Proviron, Emilio’s research will exploit the identified metabolic activities of bacteria to test if other commercially relevant algae can be influenced via modulation of signal molecules. The results expected from Emilio’s research are:

  • the universality of the concepts developed will be verified in benthic bacteria/diatom interactions in cooperation with the University of Constance and the University of Ghent;
  • and a commercially relevant algae in bioreactors will be manipulated along the established general concepts of bacterial interference with biofilm signaling. This will also include other algal taxonomic groups (see Projects 10-12).