Kidney transcriptome analysis of tiger puffer (Takifugu rubripes) uncovers key pathways and genes in response to low-temperature stress

Abstract

The tiger puffer (Takifugu rubripes) is an important economic fish species in northern China; however, cold stress during overwintering can have serious adverse effects on its aquaculture. Understanding the mechanisms of cold resistance in tiger puffers will thus provide critical information regarding its overwintering process. Here, we compared tiger puffer kidney transcriptomes at 5 °C and 23 °C to identify the key pathways and genes involved in the response to low temperature stress. We identified a total of 1679 differentially expressed genes (DEGs), including 635 up-regulated genes and 1044 down-regulated genes in the 5 °C compared with the 23 °C group. Kyoto Encyclopedia of Genes and Genomes enrichment analysis indicated five significantly enriched pathways, four of which were related to metabolism. Transcriptome data and quantitative polymerase chain reaction verification showed that most of the DEGs were down-regulated, with a ratio of down-regulated to up-regulated genes of 26:6, among the three significantly enriched pathways involving amino acid and lipid metabolism. Further analysis of the up-regulated genes showed that the arginine and proline pathway was the primary signaling pathway, and that the two metabolic pathways for arginine (including nitric oxide synthase and arginase) were likely to be key factors affecting cold resistance in tiger puffers. Diet supplementation with arginine may thus improve cold tolerance in tiger puffers. These results provided new insights into the stress impact of the aquaculture environment on tiger puffers from the perspective of nutrition.