Taxonomic and metabolic shifts in the Coorong bacterial metagenome driven by salinity and external inputs

作     者：Kelly NEWTON Thomas C.JEFFRIES Renee J.SMITH Justin R.SEYMOUR Laurent SEURONT James G.MITCHELL 

作者机构：School of Biological SciencesFlinders University School of Science and HealthWestern Sydney University Flinders Centre for Innovation in CancerFlinders University Climate Change ClusterUniversity of Technology Sydney Centre National de la Recherche Scientifi queLaboratoire d'Océanologie et de Géosciences 

出 版 物：《Journal of Oceanology and Limnology》 (海洋湖沼学报（英文）)

年 卷 期：2018年第36卷第6期

页      面：2033-2049页

核心收录：

学科分类：07[理学] 

基　　金：Department of Environment and Natural Resources (DENR) for allowing us access to the Coorong National Park (permit number G25583-2) supported by the Australian Research Council by Flinders University 

主　　题：hypersaline estuary bacteria taxonomy metabolic potential 

摘      要：The Coorong estuary lies at the terminus of Australia s largest river system, the Murray-Darling; both are strongly influenced by human activities; including farming and extensive flow modification. Metagenomic approaches were used to determine the planktonic bacterial community composition and potential metabolic function at two extremes in the Coorong, the river mouth which exhibits marine-like salinity, and the hypersaline upper-reaches of the estuary. Significant shifts in taxa and metabolic function were seen between the two sites. The river mouth exhibited an increase in abundance of R hodobacteriaceae and Alteromonadaceae; families readily able to adapt to change in nutrient conditions; and the potentially pathogenic families B rucellaceae, Enterobacteriaceae and Vibrionaceae. Metabolisms over-represented include motility and chemotaxis, RNA metabolism and membrane transport, all of which are involved in actively searching for and obtaining nutrients. Also over-represented were metabolisms involved in population succession and stress response. An over-representation of taxa and metabolisms indicative of environmental change is reflective of anthropogenically af fected riverine input. In the hypersaline upper reaches of the estuary, the halophilic family Ectothiorhodospiraceae was over-represented, as were the families Flavobacteriaceae, Cytophagaceae and Nocardioidaceae, members of which are able to survive over a wide salinity range. Metabolisms over-represented here were reflective of increased bacterial growth, characteristic of hypersaline environments, and included DNA metabolism, nucleotide and nucleoside synthesis and cell cycle. Coorong metagenomes clustered taxonomically and metabolically with other planktonic metagenomes, but remained an outlier of this group with only 71% and 84% similarity, respectively. This indicates that the Coorong exhibits a unique planktonic bacterial community that is influenced by riverine input at the river mouth and sali