PHYCOCYP · PHYtoplankton responses to organic COntaminants: the role of CYtochrome P450

Anthropic activities result in a continuous release of Organic Contaminants (OCs) in the aquatic environment and chemical pollution may considerably affect phytoplankton that are photosynthetic microorganisms playing a major role in aquatic ecosystems. Adverse outcomes of OCs on phytoplankton are directly linked to the ability of the organism to face the toxic insult. OCs may be metabolized to less toxic compounds activating poorly understood biotransformation processes. The main objective of the PHYCOCYP project is to improve the mechanistic understanding of biotransformation processes and their role in phytoplankton tolerance to OCs. Among the numerous enzymes involved in xenobiotic biotransformation, a key role is played by Cytochrome P450 (CYPs). CYPs are found in all domains of life and were extensively studied in higher organisms. However, little information is available on the role of CYPs in OC biotransformation and tolerance in phytoplankton. The PHYCOCYP project will address this knowledge gap. Recent genomic studies highlighted the presence of multiple CYP genes in phytoplankton species and toxicological studies indicated their involvement in phytoplankton responses to OC exposure. In the proposed research, an initial screening will investigate whether CYP genes expression is conserved in different phytoplankton classes exposed to OCs with different modes of action. The involvement of CYPs in OC biotransformation and tolerance will be then assessed in a model phytoplankton specie integrating a genetic approach to physiological investigations and metabolic profiling of OC transformation products. Aquatic environment preservation and restoration is one of the main contemporary environmental challenges. Knowledge generated with PHYCOCYP project will help evaluate the potential impact of OC on key organisms of aquatic ecosystems and may serve for the implementation of biotransformation processes for OC removal and pollution remediation.