Team

Panorama

Integrative physiology and adaptation of marine organisms: from genes to population

Marine coastal areas are particularly exposed to the increasing impact of human activities (urbanisation, pollution, eutrophication). They are also exposed to the effects of global change with sudden and strong variations of several biotic and abiotic parameters (i.e. temperature, oxygen, pH, salinity, currentology, contaminants, trophic conditions). These variations can lead to changes in phytoplankton communities, emergence of pathogens and changes in the specific composition (native or non-native species) of coastal environments. Organisms living in these coastal areas must adapt to these changing environments to maximize their fitness. Understanding the sustainable assemblage of species within communities and their evolution requires knowledge of biotic interactions. Understanding individual adaptive responses in terms of life history traits (or more broadly quantitative biological traits) and integrating their consequences at the population level is also necessary to predict the evolution of biotic interactions and the emergence of harmful species in a changing environment. PANORAMA scientific project is part of this general context. The team strategy is based on the control and integration of a wide range of methodological approaches applied at different organizational levels (epigenetic markers, gene expression, protein functions, physiological performance and behaviour) through in situ, in vivo and in vitro studies.

PANORAMA is structured around 6 Research Axes (AR). AR1 and AR2 examine the physiological processes involved in fluctuating environments, and the long-term effects of adaptive processes, distinguishing between phenotypic and genetic responses. AR 3, 4 and 5 aim at better understanding trophic and species interactions by taking into account environmental variability. Finally, in AR6 our research activities target the economic valorisation exploiting the knowledge of metabolic processes and properties of certain marine molecules.

Research Axis 1 : "Population structure and adaptation"

Animators : G. Charrier (UBO) & S. Roussel (UBO).

In the face of environmental change, marine populations can adapt in response to selection forces over generations. However, the adaptive potential of natural populations is conditioned by their degree of genetic variability, which results from their evolutionary history (Figure 8). A better understanding of historical and contemporary processes shaping the genetic diversity of natural populations is therefore necessary to disentangle the processes governing their adaptation to local environmental pressures. In addition, domestic populations can have a significant impact on the genetic diversity of natural conspecific populations, and thus alter their adaptive potential in the face of environmental changes.

The main objectives of RA1 will assess the genetic structure of natural populations (RA1.1) and explore local adaptation patterns in contrasted environments (RA1.2). In addition, interactions between domestic and wild populations will be studied in order to estimate their impact on the evolutionary and adaptive potential of natural populations (RA1.3).

RA1.1 “Structure of marine populations”

RA1.2 “Local adaptation”

RA1.3 “Interactions beetween wild populations and breeding and domestication”

Research Axis 2 : "Acclimatization and life trajectories_ Phenotypic plasticity"

Animators : D. Mazurais (Ifremer) & C. Corporeau (Ifremer)

In addition to local adaptation (see RA1), phenotypic plasticity is an essential component of the ability of marine populations to respond to new environmental constraints. Our research shows that phenotypic plasticity affects a very wide range of life traits related to the development, physiology, morphology and behaviour of organisms. Our work also shows that while phenotypic plasticity is more pronounced in the early stages of life (embryo and larvae), it is still largely predominant in later stages (juvenile and adult). We have thus demonstrated that the effect of the environment on the phenotypic architecture of marine organisms is an important determinant of their life trajectory.

In this context, understanding the energy constraints and underlying trade-offs that will modulate life trajectories are central elements of our prospective because they are essential to understanding adaptive and evolutionary processes. The objectives of the RA2 are therefore:

examine the relationship (and thus trade-offs) between the physiological and behavioural dimensions of the response of marine organisms to environmental constraints
to study the impact of environmental history on certain life traits and the mechanisms underlying them (including epigenetics).

RA2.1 “Behavior”

RA2.2 “Physiological determinants (Nutrition, reproduction, energy metabolism, growth, cardiac function)”.

RA2.3 “Early conditioning and epigenetics”

Research Axis 3 : "Responses to phycotoxins, diffuse pollution and emerging contaminants: ecotoxicological approach"

Animators : A. Huvet (Ifremer) & J. Laroche (UBO).

Toxic substances of “natural” origin or resulting from human activities constitute a wide range of contaminants that generate potential risks for the ecosystem. This research axis aims to develop ecotoxicological approaches in the marine environment, consisting in exploring the fate and effects of these substances, particularly emerging pollutants (phycotoxins synthesized by certain micro-algae, micro- and nanoplastics, drug residues) and diffuse pollution (due to multiple anthropogenic releases), on organisms and populations in coastal areas. We study the mechanisms of bioaccumulation, purification and biological disturbances generated in marine organisms at each stage of development (gametes, embryos, larvae, juveniles, adults, transgenerational effect) in response to contaminants under different scenarios, acute toxicity, chronic toxicity, cocktail effect. LEMAR also participates in the assessment of contamination levels on the French coast, an important prerequisite for estimating the probability of exposure. The ecotoxicological approach proposed here is fully in line with the framework of an Aquatic Ecotoxicology Network currently being set up at national level, led by IRSTEA-Lyon, and in which LEMAR is a partner; and a PHYCOTOX Research Group on toxic algae and their toxins, of which LEMAR is a co-leader. The ecotoxicology network aims to identify the potential of new “-omics” approaches in an integrative approach to acquire a better knowledge of impacts, to characterize the vulnerability of organisms and populations to chemical stress, and finally to better understand the differential sensitivity of species, a current source of uncertainty in order to consolidate the ecotoxicological assessment of natural environments. The PHYCOTOX GdR has an axis involving the impact of toxic and harmful microalgae and their toxins on marine organisms. Lastly, the Polymers and Ocean GDR, created in 2019, LEMAR being in the scientific comity, aims to stimulate interdisciplinary research among French laboratories working on plastic wastes in aquatic environments. The LEMAR is mostly implicated in the axis Impact and risk assessment.

Research Axis 4 : Environment-Host-Pathogen-Microbiota Interactions (IEHPM)

Animators : F. Pernet (Ifremer) & C. Paillard (CNRS)

In recent years, human activities associated with evolutionary processes and climate change have exacerbated the emergence and severity of many diseases in marine shellfish. Massive deaths of species of economic interest have been associated with bacteria, such as Vibrio and Herpes viruses, of a particular genotype (OsHV-1 μvar). However, the defense mechanisms, and their molecular bases, allowing some undivided individuals to effectively resist their pathogens are not elucidated. Similarly, virulence factors specifically involved in the development of disease have not yet been studied in an evolutionary framework associated with climate change. Finally, the role of environmental parameters, including farming practices, on disease transmission in the marine environment is not well known. The observation of shellfish populations with different levels of susceptibility to their respective pathogens and the recent development of genomic information in shellfish provide the tools necessary to characterize the resistance mechanisms specific to each species of shellfish. In addition, advances in microbial ecology, thanks to high throughput sequencing techniques, have led us to take into account the entire community of microorganisms that make up the microbiota, in close relationship with the environment-host-pathogen tryptic. The objective of this RA 4 will be to better understand the mechanisms governing the development of shellfish diseases (vibriosis and viruses) at different spatial and temporal scales and at different levels of organization, modulated by environmental factors. This RA4’s research will focus on:

the physiological response of the host and in particular the immune response;
virulence factors of pathogens;
environment-host-host-pathogen-microbial interactions.

RA4.1 “Physiological response of the host”

RA4.2 “Virulence factors of pathogens”

RA4.3 The Host-pathogen-microbiota system and its modulation

Research Axis 5: "Chemical Ecology of Marine Organisms" (ECOM)

Animators : Valérie Stiger (UBO) & Sylvain Petek (IRD).

Chemical ecology is a multidisciplinary field of research, involving a diversity of scientific and technical approaches. Chemical ecology consists of the study of interactions between organisms, and with their environment, mediated by molecules in all their diversity and complexity.

In temperate, tropical and polar environments, marine organisms present physiological adaptations to biotic and abiotic constraints, by producing original primary and/or secondary metabolites, or by selecting a microbiota with a specific surface area and producing defence metabolites; these adaptations thus play a very important role in the community structuring.

The chemical ecology research axis studies the interactions between species, but also the influence of environmental variations on these interactions and on the organisms inhabiting these ecosystems. In addition, following the isolation of defence molecules, this RA also makes possible to consider biotechnological applications of metabolites (link with RA6). Indeed, the communication or protection molecules isolated in this RA5 can be proposed as marine active ingredients and then can be used in various industrial sectors.

This RA5 is structured in 4 sub-axes allowing to cover all the team’s themes related to chemical ecology. Different models are studied: microalgae, macroalgae, sponges, alcyonaria and their associated microflora.

RA5.1 “Chemical adaptation to abiotic factors: photoprotection, osmoregulation, thermoregulation”.

RA5.2 “Chemical adaptation to biotic factors: grazing and allelopathy”

RA5.3 “Quorum sensing”

RA5.4 “Adhesion mechanisms – activation, inhibition”

Research Axis 6 : "Biotechnological valorization of seafood products (aquaculture, food, health, cosmetics)

Animators : C. Hellio (UBO) & P. Soudant (CNRS).

The enhancement of marine organisms is currently a major societal challenge for the production of new food resources (i.e. to fill the growing global deficit in proteins and omega 3 lipids) but also to provide new molecules in the fields of human, animal and plant health as well as in the field of biomaterials.

This RA6 is part of a continuum between fundamental research developed in other RAs and applied research. It will be based not only on the disciplinary expertise (ecology, biochemistry, molecular biology, and microbiology) of the members of Team 1 but also on the diversity of the biological models studied (bacteria, microalgae, macroalgae, halophytes, molluscs, fish) and their co-products.

This RA also benefits from two LEMAR technological platforms BIODIMAR® and LIPIDOCEAN, which are at the forefront of screening, fine analysis and purification methods.

Downstream, it will consolidate the strong links established during the previous five-year period with economic actors in the West of France.

RA 6.1 Biomimetic approaches

RA 6.2 Biotechnological applications of chemical ecology

RA 6.3 Development of anti-biofilm and antifouling strategies

RA 6.4 Industrial outcomes of marine lipids