{"id":{"repo_id":"exeter","oai_identifier":"oai:figshare.com:article/32415222"},"canonical_url":"https://search.dev.ndltd.org/etd/exeter/oai:figshare.com:article/32415222","repository":{"repo_id":"exeter","name":"University of Exeter","base_url":"https://api.figshare.com/v2/oai"},"display":{"title":"Environmental and Biotic Drivers of Seaweed–Bacterial Interactions: Insights into the Seaweed Holobiont","abstract":"Seaweeds are host to a wide variety of microbes with which they form chemically mediated relationships, operating as a unified holobiont - an integrated functional unit. Host fitness is reliant on this symbiosis, with interactions from epiphytic bacteria necessary for the correct physiological functioning, health, development, and resilience of the seaweed. As seaweeds provide a plethora of ecosystem services and commercial benefits, understanding these interactions and how they affect host condition and viability is important. This thesis aims to investigate how environmental and biotic pressures impact the seaweed holobiont, using a combination of manipulative experiments and multi-omics techniques. The thesis begins by broadly introducing the composition, function and potential pressures facing the seaweed holobiont (Chapter 1). Due to the rapid increase of seaweed aquaculture and the subsequent rise in disease prevalence, Chapter 2 conducts a comprehensive review of seaweed bacterial pathogen diversity and the emerging management strategies used in disease mitigation. As seaweed microbiomes are diverse and frequently species-specific, with the host able to actively attract and repel settling bacteria, Chapter 3 investigates fundamental mechanisms influencing holobiont assembly. Through conducting reciprocal transplant experiments, we demonstrate that seaweed-associated bacteria are locally adapted to their host species, with bacterial isolates exhibiting significantly higher fitness in their native host environment. Chapter 4 then investigates how broader environmental stressors, such as climate change, affects host metabolism by exposing a model seaweed species to a combination of two stressors: infection and thermal stress. These two stressors resulted in the significant up-regulation of several osmolytes such as trigonelline and 2-homoectoine, which could serve as future stressor markers. The impact of mean temperature rise on host-microbiome interactions is then explored through examining shifts in seaweed surface chemistry, bacterial taxonomy and host genes (Chapter 5). Bacterial communities, key compounds, and genes associated with DNA damage responses, ribosomal assembly and cell cycle control were found to shift, implying detrimental consequences for the health of seaweeds under future temperature scenarios. Through combining ecological experiments with monitoring shifts in microbial community compositions and holobiont molecular processes, this thesis provides novel insights into the mechanisms underlying holobiont resilience and stability under environmental change and infection. This thesis, therefore, contributes to the growing body of research exploring the evolutionary and ecological drivers that shape bacterial communities, with implications for ecosystem management, disease control and microbial biotechnology.<p></p>","abstract_html":"Seaweeds are host to a wide variety of microbes with which they form chemically mediated relationships, operating as a unified holobiont - an integrated functional unit. Host fitness is reliant on this symbiosis, with interactions from epiphytic bacteria necessary for the correct physiological functioning, health, development, and resilience of the seaweed. As seaweeds provide a plethora of ecosystem services and commercial benefits, understanding these interactions and how they affect host condition and viability is important. This thesis aims to investigate how environmental and biotic pressures impact the seaweed holobiont, using a combination of manipulative experiments and multi-omics techniques. The thesis begins by broadly introducing the composition, function and potential pressures facing the seaweed holobiont (Chapter 1). Due to the rapid increase of seaweed aquaculture and the subsequent rise in disease prevalence, Chapter 2 conducts a comprehensive review of seaweed bacterial pathogen diversity and the emerging management strategies used in disease mitigation. As seaweed microbiomes are diverse and frequently species-specific, with the host able to actively attract and repel settling bacteria, Chapter 3 investigates fundamental mechanisms influencing holobiont assembly. Through conducting reciprocal transplant experiments, we demonstrate that seaweed-associated bacteria are locally adapted to their host species, with bacterial isolates exhibiting significantly higher fitness in their native host environment. Chapter 4 then investigates how broader environmental stressors, such as climate change, affects host metabolism by exposing a model seaweed species to a combination of two stressors: infection and thermal stress. These two stressors resulted in the significant up-regulation of several osmolytes such as trigonelline and 2-homoectoine, which could serve as future stressor markers. The impact of mean temperature rise on host-microbiome interactions is then explored through examining shifts in seaweed surface chemistry, bacterial taxonomy and host genes (Chapter 5). Bacterial communities, key compounds, and genes associated with DNA damage responses, ribosomal assembly and cell cycle control were found to shift, implying detrimental consequences for the health of seaweeds under future temperature scenarios. Through combining ecological experiments with monitoring shifts in microbial community compositions and holobiont molecular processes, this thesis provides novel insights into the mechanisms underlying holobiont resilience and stability under environmental change and infection. This thesis, therefore, contributes to the growing body of research exploring the evolutionary and ecological drivers that shape bacterial communities, with implications for ecosystem management, disease control and microbial biotechnology.&lt;p&gt;&lt;/p&gt;","abstract_has_math":false,"creators":["Shauna Corr (21041330)"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-05-20T00:00:00Z","date_published":"2026-05-20T00:00:00Z","updated_at":"2026-07-27T19:32:54Z","subjects":["Holobiont","Seaweed","Macroalgae","Bacterial Interactions","Host-microbe","microbiome"],"languages":[],"rights":["All rights reserved"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["10779/exe.32415222.v1"],"render_values":[{"text":"10779/exe.32415222.v1","href":null,"code":true}]}]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Shauna Corr (21041330)"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2026-05-20T00:00:00Z"]},{"key":"dc:relation","label":"Dc Relation","values":["https://figshare.com/articles/thesis/Environmental_and_Biotic_Drivers_of_Seaweed_Bacterial_Interactions_Insights_into_the_Seaweed_Holobiont/32415222"]},{"key":"dc:type","label":"Dc Type","values":["Text","Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Holobiont","Seaweed","Macroalgae","Bacterial Interactions","Host-microbe","microbiome"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["All rights reserved"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["10779/exe.32415222.v1"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Seaweeds are host to a wide variety of microbes with which they form chemically mediated relationships, operating as a unified holobiont - an integrated functional unit. Host fitness is reliant on this symbiosis, with interactions from epiphytic bacteria necessary for the correct physiological functioning, health, development, and resilience of the seaweed. As seaweeds provide a plethora of ecosystem services and commercial benefits, understanding these interactions and how they affect host condition and viability is important. This thesis aims to investigate how environmental and biotic pressures impact the seaweed holobiont, using a combination of manipulative experiments and multi-omics techniques. The thesis begins by broadly introducing the composition, function and potential pressures facing the seaweed holobiont (Chapter 1). Due to the rapid increase of seaweed aquaculture and the subsequent rise in disease prevalence, Chapter 2 conducts a comprehensive review of seaweed bacterial pathogen diversity and the emerging management strategies used in disease mitigation. As seaweed microbiomes are diverse and frequently species-specific, with the host able to actively attract and repel settling bacteria, Chapter 3 investigates fundamental mechanisms influencing holobiont assembly. Through conducting reciprocal transplant experiments, we demonstrate that seaweed-associated bacteria are locally adapted to their host species, with bacterial isolates exhibiting significantly higher fitness in their native host environment. Chapter 4 then investigates how broader environmental stressors, such as climate change, affects host metabolism by exposing a model seaweed species to a combination of two stressors: infection and thermal stress. These two stressors resulted in the significant up-regulation of several osmolytes such as trigonelline and 2-homoectoine, which could serve as future stressor markers. The impact of mean temperature rise on host-microbiome interactions is then explored through examining shifts in seaweed surface chemistry, bacterial taxonomy and host genes (Chapter 5). Bacterial communities, key compounds, and genes associated with DNA damage responses, ribosomal assembly and cell cycle control were found to shift, implying detrimental consequences for the health of seaweeds under future temperature scenarios. Through combining ecological experiments with monitoring shifts in microbial community compositions and holobiont molecular processes, this thesis provides novel insights into the mechanisms underlying holobiont resilience and stability under environmental change and infection. This thesis, therefore, contributes to the growing body of research exploring the evolutionary and ecological drivers that shape bacterial communities, with implications for ecosystem management, disease control and microbial biotechnology.<p></p>"]},{"key":"dc:title","label":"Title","values":["Environmental and Biotic Drivers of Seaweed–Bacterial Interactions: Insights into the Seaweed Holobiont"]}]}],"canonical_facts":{"dc:creator":["Shauna Corr (21041330)"],"dc:date":["2026-05-20T00:00:00Z"],"dc:description":["Seaweeds are host to a wide variety of microbes with which they form chemically mediated relationships, operating as a unified holobiont - an integrated functional unit. Host fitness is reliant on this symbiosis, with interactions from epiphytic bacteria necessary for the correct physiological functioning, health, development, and resilience of the seaweed. As seaweeds provide a plethora of ecosystem services and commercial benefits, understanding these interactions and how they affect host condition and viability is important. This thesis aims to investigate how environmental and biotic pressures impact the seaweed holobiont, using a combination of manipulative experiments and multi-omics techniques. The thesis begins by broadly introducing the composition, function and potential pressures facing the seaweed holobiont (Chapter 1). Due to the rapid increase of seaweed aquaculture and the subsequent rise in disease prevalence, Chapter 2 conducts a comprehensive review of seaweed bacterial pathogen diversity and the emerging management strategies used in disease mitigation. As seaweed microbiomes are diverse and frequently species-specific, with the host able to actively attract and repel settling bacteria, Chapter 3 investigates fundamental mechanisms influencing holobiont assembly. Through conducting reciprocal transplant experiments, we demonstrate that seaweed-associated bacteria are locally adapted to their host species, with bacterial isolates exhibiting significantly higher fitness in their native host environment. Chapter 4 then investigates how broader environmental stressors, such as climate change, affects host metabolism by exposing a model seaweed species to a combination of two stressors: infection and thermal stress. These two stressors resulted in the significant up-regulation of several osmolytes such as trigonelline and 2-homoectoine, which could serve as future stressor markers. The impact of mean temperature rise on host-microbiome interactions is then explored through examining shifts in seaweed surface chemistry, bacterial taxonomy and host genes (Chapter 5). Bacterial communities, key compounds, and genes associated with DNA damage responses, ribosomal assembly and cell cycle control were found to shift, implying detrimental consequences for the health of seaweeds under future temperature scenarios. Through combining ecological experiments with monitoring shifts in microbial community compositions and holobiont molecular processes, this thesis provides novel insights into the mechanisms underlying holobiont resilience and stability under environmental change and infection. This thesis, therefore, contributes to the growing body of research exploring the evolutionary and ecological drivers that shape bacterial communities, with implications for ecosystem management, disease control and microbial biotechnology.<p></p>"],"dc:identifier":["10779/exe.32415222.v1"],"dc:relation":["https://figshare.com/articles/thesis/Environmental_and_Biotic_Drivers_of_Seaweed_Bacterial_Interactions_Insights_into_the_Seaweed_Holobiont/32415222"],"dc:rights":["All rights reserved"],"dc:subject":["Holobiont","Seaweed","Macroalgae","Bacterial Interactions","Host-microbe","microbiome"],"dc:title":["Environmental and Biotic Drivers of Seaweed–Bacterial Interactions: Insights into the Seaweed Holobiont"],"dc:type":["Text","Thesis"]},"updated_at":"2026-07-27T19:32:54Z"}