|Institution:||University of New South Wales|
|Department:||Biotechnology & Biomolecular Sciences|
|Keywords:||Microbialite; Stromatolite; Microbial Mat; Shark Bay|
|Full text PDF:||http://handle.unsw.edu.au/1959.4/54218|
The living stromatolites of Shark Bay on the western coast of Australia are marine systems that present unique opportunities to address fundamental questions in diverse fields ranging from microbiology, geology, evolution, functional genomics, and biotechnology. They are one of the most dominant and persistent parts of Earth’s fossil records and thus highly significant from evolutionary and ecological perspectives. Also, these stromatolites are an ideal biological system for studying survival strategies of resident microorganisms, as well as the potential for novel bioactive discovery. Previous studies utilising culture and non-culture methods confirmed the high diversity of microbial life in this environment. To further our understanding of these geobiological structures, detailed analyses of associated microbial communities and their functional characteristics are crucial. The emergence of next-generation sequencing technologies provides unprecedented access to detailed genetic information on the systems in Shark Bay, and allows us to address fundamental ecological, adaptive, and evolutionary questions. To further delineate microbial community composition and elucidate for the first time the genetic potential of the resident communities, in this study, we have sequenced two distinct stromatolitic mat metagenomes by 454 shotgun pyrosequencing and 16S rDNA tagging. The libraries were annotated using the MetaGenomic Rapid Annotation using Subsystem Technology (MG-RAST) and Integrated Microbial Genome with Microbiome Samples-Expert Review (IMG/MER). In addition to phylogenetic analyses, we focused on key subsystems and identified the diversity and abundance of genes involved in critical processes such as a stromatolite formation (e.g. EPS turnover, nutrient cycling), adaptive responses (e.g. osmo, antibiotics and heavy metal), cell communication (e.g. quorum sensing), and bioactive production (eg. non-ribosomal peptide synthesis). Clustering analyses of the different stromatolites samples, based primarily on subsystems, have revealed processes that are shared in a given sample and potentially distinguish the Shark Bay stromatolites from other ecosystems. The functional genetic complexity of microorganisms associated with the Shark Bay stromatolites has been shown for the first time and vastly improves our understanding of these ancient ecosystems, while providing a platform to further explore the potential of these systems at the expression level.