Genetic and chemical diversity of Microcystis cyanobacteria and associated ecotoxicity – MCtox

Besides anthropogenic pollutants, proliferations of phytoplanktonic cyanobacteria in freshwater ecosystems represent a source of growing concern worldwide due to the ecological and economical disturbances they create, as well as the significant impact of their toxins on animal and human health. One of the most prevalent and notorious bloom-forming genera of freshwater cyanobacteria is Microcystis, whose toxicological impairs yet remain incompletely investigated. We hypothesize that some emerging Microcystis metabolites (in addition to microcystins (MCs)) are of (eco)toxicological concern and should be included in future environmental monitoring and sanitary regulations. This research proposal is then both novel and timely for ecotoxicological and human risk assessment, by providing the first large scale screening of emerging Microcystis noxious metabolite diversity that has never been performed previously.
Accordingly, the main objective of the “MC Tox” project is to identify, the most potentially noxious Microcystis metabolites, apart from MCs. It requires purifying and characterizing them, when unknown, to describe their respective biosynthetic gene clusters (BGCs), in addition to characterizing their specific toxicological range and to providing reference material for their absolute quantification. To meet the aforementioned challenges, “MC Tox” project will be structured into 4 work packages carried out by a 3-partner consortium including MCAM from MNHN, PCC from Institut Pasteur, and SEBIO from Univ. Reims-Champagne-Ardennes. It will be focussed on: 1/ the description of the chemical diversity of Microcystis genotypes retrieved by genome mining and metabolomics from mono-clonal strains; 2/ the purification and the characterization of most potentially toxic Microcystis metabolites (except MCs); 3/ the genome editing of Microcystis strains for specific novel BGC identification; 4/ the toxicological characterization of the Microcystis chemical diversity.