@article {7122, title = {Laminariales Host Does Impact Lipid Temperature Trajectories of the Fungal Endophyte Paradendryphiella salina (Sutherland.)}, journal = {Marine Drugs}, volume = {18}, year = {2020}, pages = {379}, abstract = {Kelps are colonized by a wide range of microbial symbionts. Among them, endophytic fungi remain poorly studied, but recent studies evidenced yet their high diversity and their central role in algal defense against various pathogens. Thus, studying the metabolic expressions of kelp endophytes under different conditions is important to have a better understanding of their impacts on host performance. In this context, fatty acid composition is essential to a given algae fitness and of interest to food web studies either to measure its nutritional quality or to infer about its contribution to consumers diets. In the present study,\ Paradendryphiella salina, a fungal endophyte was isolated from\ Saccharina latissima\ (L.) and\ Laminaria digitata\ (Hudson.) and its fatty acid composition was assessed at increasing salinity and temperature conditions. Results showed that fungal composition in terms of fatty acids displayed algal-dependent trajectories in response to temperature increase. This highlights that C18 unsaturated fatty acids are key components in the host-dependant acclimation of\ P. salina\ to salinity and temperature changes}, keywords = {fatty acids, fungal endophytes, laminariales, Paradendryphiella salina}, doi = {10.3390/md18080379}, url = {https://www.mdpi.com/1660-3397/18/8/379}, author = {Vallet, Marine and Tarik Meziane and Najet Thiney and Prado, Soizic and C{\'e}dric Hubas} } @article {7216, title = {Novel α-Hydroxy γ-Butenolides of Kelp Endophytes Disrupt Bacterial Cell-to-Cell Signaling}, journal = {Frontiers in Marine Science}, volume = {7}, year = {2020}, month = {Jun-07-2022}, doi = {10.3389/fmars.2020.0060110.3389/fmars.2020.00601.s001}, url = {https://www.frontiersin.org/article/10.3389/fmars.2020.00601/full}, author = {Vallet, Marine and Chong, Yee-Meng and Tourneroche, Anne and Genta-Jouve, Gregory and C{\'e}dric Hubas and Lami, Rapha{\"e}l and Gachon, Claire M. M. and Klochkova, Tatyana and Chan, Kok-Gan and Prado, Soizic} } @article {6911, title = {An Untargeted Metabolomic Approach for Microphytobenthic Biofilms in Intertidal Mudflats}, journal = {Frontiers in Marine Science}, volume = {7}, year = {2020}, pages = {250}, abstract = {Microphytobenthic (MPB) biofilms in intertidal muddy sediments play important ecological functions in coastal ecosystems. These biofilms are mainly composed of epipelic diatoms but also prokaryotes, with a dominance of bacteria, which excrete diverse extracellular polymeric substances (EPS) according to their environment. While numerous studies have investigated the main components of these EPS matrices via traditional colorimetric assays, their fine composition, notably in specialized metabolites, is still largely unknown. A better chemical characterization of these MPB biofilms is necessary, especially regarding the numerous functions their chemical components play for microorganisms (e.g., motility, cell protection, defense mechanisms, and chemical communication), but also for coastal systems (e.g., primary production, sediment stabilization, larval settlement of some invertebrates with high economical value). An alternative approach to traditional analyses is the use of untargeted metabolomic techniques, which have not yet been applied to such MPB biofilms. The objectives of the present study were to (a) propose a protocol for metabolic fingerprinting by LC-MS and GC-MS for metabolites analysis in polar and non-polar fractions in MPB biofilms extracted from mudflat sediment and to (b) apply this protocol to a case study: the effect of light exposure on the metabolomic fingerprint of the MPB biofilm community. We compared three extraction methods using different mixes of solvents and selected a methanol/chloroform mix (1:1), which gave better results for both techniques and fractions. We then applied the selected protocol to our case study using a short-term light exposure experiment in aquaria (7 days). The present study is the first using a detailed untargeted metabolomic approach on MPB biofilms from mudflat sediment and will provide a solid baseline for further work in this area.}, issn = {2296-7745}, doi = {10.3389/fmars.2020.00250}, url = {https://www.frontiersin.org/article/10.3389/fmars.2020.00250}, author = {Gaubert-Boussarie, Julie and Prado, Soizic and C{\'e}dric Hubas} } @article {6077, title = {Bacterial{\textendash}Fungal Interactions in the Kelp Endomicrobiota Drive Autoinducer-2 Quorum Sensing}, journal = {Frontiers in Microbiology}, volume = {10}, year = {2019}, pages = {1693}, abstract = {

Brown macroalgae are an essential component of temperate coastal ecosystems and a growing economic sector. They harbor diverse microbial communities that regulate algal development and health. This algal holobiont is dynamic and achieves equilibrium via a complex network of microbial and host interactions. We now report that bacterial and fungal endophytes associated with four brown algae (Ascophyllum nodosum, Pelvetia canaliculata, Laminaria digitata, and Saccharina latissima) produce metabolites that interfere with bacterial autoinducer-2 quorum sensing, a signaling system implicated in virulence and host colonization. Additionally, we performed co-culture experiments combined to a metabolomic approach and demonstrated that microbial interactions influence production of metabolites, including metabolites involved in quorum sensing. Collectively, the data highlight autoinducer-2 quorum sensing as a key metabolite in the complex network of interactions within the algal holobiont.

}, issn = {1664-302X}, doi = {10.3389/fmicb.2019.01693}, url = {https://www.frontiersin.org/article/10.3389/fmicb.2019.01693}, author = {Tourneroche, Anne and Lami, Rapha{\"e}l and C{\'e}dric Hubas and Blanchet, Elodie and Vallet, Marine and Escoubeyrou, Karine and Paris, Alain and Prado, Soizic} } @article {6078, title = {Chemically-Mediated Interactions Between Macroalgae, Their Fungal Endophytes, and Protistan Pathogens}, journal = {Frontiers in Microbiology}, volume = {9}, year = {2018}, pages = {3161}, abstract = {

Filamentous fungi asymptomatically colonise the inner tissues of macroalgae, yet their ecological roles remain largely underexplored. Here, we tested if metabolites produced by fungal endophytes might protect their host against a phylogenetically broad spectrum of protistan pathogens. Accordingly, the cultivable fungal endophytes of four brown algal species were isolated and identified based on LSU and SSU sequencing. The fungal metabolomes were tested for their ability to reduce the infection by protistan pathogens in the algal model Ectocarpus siliculosus. The most active metabolomes effective against the oomycetes Eurychasma dicksonii and Anisolpidium ectocarpii, and the phytomixid Maullinia ectocarpii were further characterized chemically. Several pyrenocines isolated from Phaeosphaeria sp. AN596H efficiently inhibited the infection by all abovementioned pathogens. Strikingly, these compounds also inhibited the infection of nori (Pyropia yezoensis) against its two most devastating oomycete pathogens, Olpidiopsis pyropiae and Pythium porphyrae. We thus demonstrate that fungal endophytes associated with brown algae produce bioactive metabolites which might confer protection against pathogen infection. These results highlight the potential of metabolites to finely-tune the outcome of molecular interactions between algae, their endophytes and protistan pathogens. This also provide proof-of-concept towards the applicability of such metabolites in marine aquaculture to control otherwise untreatable diseases.

}, issn = {1664-302X}, doi = {10.3389/fmicb.2018.03161}, url = {https://www.frontiersin.org/article/10.3389/fmicb.2018.03161}, author = {Vallet, Marine and Strittmatter, Martina and Mur{\'u}a, Pedro and Lacoste, Sandrine and Dupont, Jo{\"e}lle and C{\'e}dric Hubas and Genta-Jouve, Gregory and Claire M. M. Gachon and Kim, Gwang Hoon and Prado, Soizic} }