Molecular Drivers of the InteractionS between marine algicidal KORdia and DIAtoms: from coexistence to algal lysis.

Interactions between marine bacteria and phytoplankton are increasingly recognized as a fundamental shaping force of microbial taxonomic and functional diversity and activity. Algicidal bacteria, found in several marine taxa, possess the ability to induce cellular lysis in marine phytoplankton.

Research on cultured strains shows a variety of algicidal properties on distinct phytoplankton host spectra among different bacterial taxa.

These observations hint to the existence of an array of diverse but poorly characterized mechanisms implicated at various stages of bacterial-phytoplankton warfare: partner recognition, triggers of lytic activity, bacterial algicidal apparatus, and phytoplankton resistance tools.

The research proposed in the DISKORDIA project named after the Roman goddess of Strife Discordia aims to provide a deeper understanding of the molecular aspects of the interactions between the algicidal marine bacterial genus Kordia and diatoms, a diverse and ecologically important phytoplankton group.

Cutting edge techniques such as transcriptomics and untargeted metabolomics will be combined to enable naive discovery of genes and metabolites potentially involved in bacterial induction and effectors of algicidal activity, and in diatom sensitivity or resistance.

In addition, genetic tools will be applied to a model Kordia strain to produce the first genetic system for algicidal bacteria in the Bacteroidetes phylum and test the role of specific bacterial genes in algal lysis.

Finally, the ecological relevance of the processes identified by these methods will be explored at a global scale by bioinformatic screening of existing metagenomic and metatranscriptomic datasets from diverse marine environments.

Together, these approaches will improve our understanding of the molecular strategies implicated in bacterial algicidal activity and phytoplankton response, while providing tools and a conceptual framework for future studies of microbial interactions.