MARBLES will use a novel and systematic approach to access and exploit marine microbial biodiversity for sustainable bioprospecting to discover microbial consortia and bioactive molecules for application in aqua- and agriculture and in the clinic. MARBLES' ecology-based bioprospecting strategy will focuses on unique host-microbe interactions in marine environments, including marine sponges, microalgae and fish, which rely on their microbiomes and microbial natural products for disease resistance. Partners’ existing microbial collections and new ones generated during MARBLES will be harnessed for the discovery of novel natural products and synthetic microbial communities. For this, MARBLES will use a systems-wide genomics approach to uncover the bioactive agents in disease-suppressive microbiomes. Also, MARBLES will explore host- and microbe-derived chemicals that elicit production of bioactive compounds, as elicitors to revitalise drug screening. The deliverables will be microbes and consortia and bioactive natural products, their derivatives and elicitors, which can be harnessed to fight infectious diseases in the agrochemical and aquaculture industries and in healthcare. Besides highly innovative, the approaches will be cost-effective and will offer advantages from both environmental and health perspectives in comparison to existing alternatives. The sustainable production of bioprotectants will increase the effectiveness of fish production - reducing the pressure on harvesting wild fish - and aid the transition of the crop agriculture sector towards bio-based and circular solutions. MARBLES will work closely together with a panel of SMEs and large companies from the EU aquaculture, crop protection biotechnology and health sectors. MARBLES fully complies with the Nagoya and Cartagena Protocols, and aims to make major contributions to the UN sustainable development goals, SDG 2, 3, 12, 13 and 14, as well as to current UN processes (BBNJ, DSI, SynBio)