Deciphering the genomic toolkit underlying animal-bacteria interactions – insights through the demosponge Amphimedon queenslandica

Yuen, Benedict Jinghao (2016). Deciphering the genomic toolkit underlying animal-bacteria interactions – insights through the demosponge Amphimedon queenslandica PhD Thesis, School of Biological Sciences, The University of Queensland. doi:10.14264/uql.2017.39

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Author Yuen, Benedict Jinghao
Thesis Title Deciphering the genomic toolkit underlying animal-bacteria interactions – insights through the demosponge Amphimedon queenslandica
Formatted title
Deciphering the genomic toolkit underlying animal-bacteria interactions – insights through the demosponge Amphimedon queenslandica
School, Centre or Institute School of Biological Sciences
Institution The University of Queensland
DOI 10.14264/uql.2017.39
Publication date 2016-12-21
Thesis type PhD Thesis
Supervisor Sandie Degnan
Andy Barnes
Total pages 222
Language eng
Subjects 0604 Genetics
Formatted abstract
All animals are inhabited by bacteria, and maintaining homeostasis in the multicellular environment of the host involves the complex balancing act of promoting the survival of symbionts while defending against intruders. Sponges (Porifera), in addition to housing diverse bacterial symbiont assemblages, also rely on bacteria filtered from the water column for nutrition. My research uses the genome-enabled demosponge, Amphimedon queenslandica, a member of one of the earliest diverging animal lineages, as an experimental platform to explore the evolutionary origin of the metazoan genomic tool-kit that mediates the molecular cross-talk between animals and bacteria. Using comparative bioinformatics tools, I characterised a surprisingly large and complex repertoire of innate immune receptors from the NLR family of genes encoded in the A. queenslandica genome. I then used a high throughput RNAseq approach to profile the sponge’s global transcriptomic response to foreign versus its own symbiotic bacteria. Conserved metazoan innate immune pathways were activated in response to both foreign and symbiotic bacteria. However, only the symbionts elicited the expression of a more extensive suite of signalling pathways, involving TGF-β signalling and the transcription factors NFκB and FoxO. Upregulation of the nutrient sensor in all treatments, AMPK, further suggests an ancient origin for the interplay between the regulation of metabolic homeostasis and immunity. Finally, I used microscopy to track the cellular processing of the different bacteria. Consistent with the transcriptional response, the symbiont bacteria were processed more rapidly than the foreign bacteria. This delay also correlated with the expression of numerous Nrf2 associated detoxification genes, indicative of cellular stress, only in response to the foreign bacteria.
Keyword Animal-bacteria interactions
Sponge
Symbiosis
Immunity
Transcriptomics
Evolution
Pattern recognition receptors
Bacteria
Genomics

Document type: Thesis
Collections: UQ Theses (RHD) - Official
UQ Theses (RHD) - Open Access
 
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Created: Wed, 07 Dec 2016, 15:02:18 EST by Mr Jinghao Benedict Yuen on behalf of Learning and Research Services (UQ Library)