Title: The microbiology of seagrasses in a changing ocean: Does environmental stress encourage seagrass pathogens?
Seagrasses have evolved from terrestrial plants while adapting to the marine environment to become a globally important ecological element within coastal ecosystems, also extremely valuable for regional economies. Aside from stabilizing the sea floor and serving as a nursery ground for several and diverse communities of juvenile finfish, shellfish, and other invertebrates, seagrasses also play a pivotal role in marine biogeochemical cycling and oxygen production. Coastal marine environments are particularly threatened by anthropogenic stressors and global climate change, and with this trend of increasing environmental decline, associated with increased pollution and rising seawater temperatures, we might expect similar increases in disease incidence in seagrasses. However, besides the reported seagrass wasting disease largely studied since 1930, there is virtually nothing known about either seagrass diseases nor their underpinning mechanisms and regulators.
Several fundamental questions regarding seagrass health remain unanswered, including: i) To what extent are Australian seagrass meadows affected by environmental perturbations? ii) Is the microbial community associated with seagrasses (holobiont) affected by environmental perturbations? iii) Does the microbial community associated with healthy (pristine) seagrass meadows differ from the microbial community associated with environmentally disturbed seagrass meadows? and iv) Are seagrasses in disturbed habitats more susceptible to disease and carrying a larger load of putative pathogens? We aim to reveal the microbial composition of seagrasses communities, using an ecogenomic approach combined with classical microbiological techniques. We will characterise and compare seagrasses microbiomes from habitats with varying conditions and levels of impact, and then potentially use disease in seagrasses as an estimator of anthropogenic influence; this will allow us to test the hypothesis that, as in corals, seagrass diseases have more intense impacts at local scales in association with anthropogenic influence. Additionally, we will perform manipulation experiments to assess the direct effect of environmental factors on the seagrass microbiome and disease incidence, coupled with mutagenic analyses of candidate pathogens to identify virulence mechanisms. The outcomes of this project will elucidate the role of the seagrass microbiome in disease and will determine how human-mediated environmental stressors affect it, ultimately providing us with better information for managing our coastal environments.
Valentina has been awarded a Faculty of Science Scholarship and an International Research Scholarship from UTS. Her research is also supported by Justin Seymour’s awarded ARC Future Fellowship Grant (opens an external site).
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