title: RNA-Seq revealed the impairment of immune defence of tilapia against the infection of Streptococcus agalactiae with simulated climate warming.
abstract: Global warming is one of the causes of disease outbreaks in fishes. Understanding its mechanisms is critical in aquaculture and fisheries. We used tilapia to study the effects of a high temperature on the infection of a bacterial pathogen Streptococcus agalactiae using RNA-Seq. We found that the dissolved oxygen level in water at 32 °C is lower than at 22 °C, and tilapia infected with the pathogen died more rapidly at 32 °C. The gene expression profiles showed significant differences in fish raised under different conditions. We identified 126 and 576 differentially expressed genes (DEGs) at 4 and 24 h post infection at 22 °C, respectively, whereas at 32 °C, the data were 312 and 1670, respectively. Almost all responding pathways at 22 °C were involved in the immune responses, whereas at 32 °C, the enriched pathways were not only involved in immune responses but also involved in oxygen and energy metabolisms. We identified significant signals of immunosuppression of immune responses at 32 °C. In addition, many of the enriched transcription factors and DEGs under positive selection were involved in immune responses, oxygen and/or energy metabolisms. Our results suggest that global warming could reduce the oxygen level in water and impair the defence of tilapia against bacterial infection.
authors.affiliation: Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Le
authors.initials: L
authors.lastname: Wang
authors.affiliation: Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.affiliation: Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Zi Yi
authors.initials: ZY
authors.lastname: Wan
authors.affiliation: Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Shu Qing
authors.initials: SQ
authors.lastname: Huang
authors.affiliation: Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Yan Fei
authors.initials: YF
authors.lastname: Wen
authors.affiliation: Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
authors.forename: Grace
authors.initials: G
authors.lastname: Lin
authors.affiliation: Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore. Electronic address: genhua@tll.org.sg.
authors.forename: Gen Hua
authors.initials: GH
authors.lastname: Yue
mesh_terms: D000818:Animals; D057231:Climate Change; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology; D006358:Hot Temperature; D011897:Random Allocation; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D013292:Streptococcus agalactiae / Q000502:physiology*; D017210:Tilapia; D059467:Transcriptome
keywords: Disease; Immune response; Oxygen metabolism; RNA-Seq; Tilapia; Warming