Molecular Interactions Between the Kelp Saccharina Latissima and Algal Endophytes Miriam Bernard
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Molecular interactions between the kelp saccharina latissima and algal endophytes Miriam Bernard To cite this version: Miriam Bernard. Molecular interactions between the kelp saccharina latissima and algal endophytes. Symbiosis. Sorbonne Université, 2018. English. NNT : 2018SORUS105. tel-02555205 HAL Id: tel-02555205 https://tel.archives-ouvertes.fr/tel-02555205 Submitted on 27 Apr 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Sorbonne Université Ecole doctorale Sciences de la Nature et de l’Homme (ED 227) Laboratoire de Biologie Intégrative des Modèles Marins UMR 8227 Equipe Biologie des algues et interactions avec l’environnement Molecular interactions between the kelp Saccharina latissima and algal endophytes Par Miriam Bernard Thèse de doctorat de Biologie Marine Dirigée par Catherine Leblanc et Akira F. Peters Présentée et soutenue publiquement le 07/09/2018 Devant un jury composé de : Dr. Florian Weinberger Chercheur GEOMAR Kiel Rapporteur Dr. Sigrid Neuhauser Chercheur Univ. Innsbruck Rapportrice Pr. Soizic Prado Professeur MNHN Examinatrice Pr. Christophe Destombe Professeur Sorbonne Université Représentant UPMC Dr. Catherine Leblanc Directrice de Recherche Directrice de thèse Dr. Akira F. Peters Chercheur Bezhin Rosko Directeur de thèse Acknowledgements First of all, I would like to thank my supervisors Catherine Leblanc and Akira Peters. You were the two most important persons to contribute to the success of this thesis. Thank you for giving me the opportunity to work on this project and for your guidance and advice over the last three years. It has really been a pleasure to work with you. I would also like to thank everyone else who has been involved in this work, in particular Sylvie Rousvoal, who not only developed several protocols with me, but also helped to improve my French. Whenever I had problems in the lab you had the ideas to make things work. Qikun Xing has provided incredible help with the analysis of the RNAseq data. Thank you so much, I would not have been able to finish this project on time without you! Here I would also like to acknowledge the advice and support from Erwan Corre during the transcriptomic analysis. Thanks also to Laurence Dartevelle for showing me how to handle the kelp cultures and for helping out with the kelp stocks and to Sandrine Boulben for the continuous detective work on the luminometer. I hope it will work forever from now on. I would also like to thank my co-authors Martina Strittmatter, Pedro Murúa, Svenja Heesch, Ga Youn Cho, Bertrand Jacquemin, Sylvie Rousvoal, Marion Ballenghien, Nadia Collet, Tristan Le Goff and Philippe Potin for their valuable attributions and the friendly collaborations. Furthermore, I am very grateful for valuable discussions of my work with the members of my thesis committee (thanks also for being spontaneous enough to move the committee meeting to my living room) and with the ABIE team. A big thank you goes to the ALFFies. You are the best! I really enjoyed all the meetings and also the time we spent together outside of the ALFF meetings, such as a crazy karaoke night in Prague and Sri’s wedding in India. Thanks also in particular to Claire Gachon who brought ALFF to life and hosted me twice during my secondments at SAMS. Here I also want to thank everyone else at SAMS for the help during my secondments in Oban. I would also like to thank Job Schipper at Hortimare and Olavur Gregersen, Urd Grandorf Bak and Nicoline Korsvold at Ocean Rainforest for giving me hands-on experience in kelp aquaculture and for being so welcoming and supportive. A very special thanks goes to Hetty KleinJan: back then when we met for the first time in Bonn, we didn’t know yet what we would get involved in. I am so happy that I had you by my side during these 3 years, not only as a colleague, but as a really good friend. Of course, I would also like to thank all my other colleagues at the station. In particular Margot Tragin, Zujaila Qui Minet, Svenja Heesch and Martina Strittmatter for being such good companions. Virginie Glippa, I guess that we sometimes might have been a bit too loud when joking around in the lab in three different languages (or the corridor…!), but you made the labwork so much better. Also, I am sure that no other lab in the station is decorated as nicely as ours. Thanks also to the “office girls”: Amandine Simeon, Maria Matard, Laure Mignerot and Eugenie Grigorian. Looking back into the past, this thesis would not have happened without Inka Bartsch and Katharina Zacher: You really aroused my love for kelps and I am incredibly thankful that I had your continuous support even during my PhD. Zum Schluss möchte ich mich bei meiner Familie und bei Valentin bedanken. Danke, dass ihr immer für mich da seid. Ihr seid meine Helden! Table of contents General Introduction .................................................................................................... 1 1. Evolutionary context of studying seaweed interactions ............................................... 1 2. Kelps .................................................................................................................................. 2 2.1 Life cycle and ecological relevance of kelps ............................................................................ 2 2.2. Global seaweed aquaculture and ecological relevance of kelps .............................................. 4 3. Pigmented algal endophytes ............................................................................................ 6 3.1 Defining algal host-endophyte interactions .............................................................................. 6 3.2 Endophytic red algae ................................................................................................................ 8 3.3 Endophytic green algae ............................................................................................................ 9 3.4 Endophytic brown algae ......................................................................................................... 10 4. Algal defence reactions against biotic stresses ............................................................ 13 4.1 Recognition of the attacker .................................................................................................... 13 4.2 Inducible defence responses ................................................................................................... 15 4.2.1 Oxidative burst ................................................................................................................ 15 4.2.2 Free fatty acids and oxylipins release ............................................................................. 16 4.2.3 Halogenation ................................................................................................................... 16 4.2.4 Transcriptomic regulation ............................................................................................... 17 4.3 Systemic responses and distance signalling ........................................................................... 20 5. Thesis project and outline ............................................................................................. 20 Chapter I. Diversity, biogeography and host specificity of kelp endophytes with a focus on the genera Laminariocolax and Laminarionema ...................................... 23 1. Introduction .................................................................................................................... 26 2. Material and Methods ................................................................................................... 28 2.1 Sampling and isolation of endophytes.................................................................................... 28 2.2 DNA extraction, barcode markers, amplification and sequencing ......................................... 28 2.3 Data analysis .......................................................................................................................... 29 3. Results ............................................................................................................................. 30 3.1 Molecular systematics ............................................................................................................ 30 3.2 Hosts and geographic origin of the isolated strains ................................................................ 34 3.3 Laminariocolax atlanticus M. Bernard, Strittmatter & A.F. Peters sp. nov. .......................... 35 4. Discussion........................................................................................................................ 37 4.1 Molecular phylogeny of kelp endophytes .............................................................................. 37 4.2 Species delimitation in Laminariocolax ................................................................................. 39 4.3 Variability of host specificity ................................................................................................