Laboratory of Environmental Pollution and Integrative Omics, Guilin Medical University, Guilin, China.
Guangxi Key Laboratory of Beibu Gulf Marine Biodiversity Conservation, Beibu Gulf University, Qinzhou, China.
mSystems. 2022 Apr 26;7(2):e0004722. doi: 10.1128/msystems.00047-22. Epub 2022 Mar 14.
Aquatic fishes face osmotic stress continuously, and the gill is the first tissue that senses and responds to the external osmotic challenges. However, the understandings of how the gill microbiota could respond to osmotic stress and their potential host-bacterium relationships are limited. The objectives of the current study are to identify the hypotonic responsive genes in the gill cells and profile the gill microbiota communities after fresh water transfer experiment via transcriptome sequencing and 16S rRNA gene sequencing. Transcriptome sequencing identified 1,034 differentially expressed genes (DEGs), such as aquaporin and sodium potassium chloride cotransporter, after the fresh water transfer. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis further highlighted the steroid biosynthesis and glycosaminoglycan biosynthesis pathways in the gill. Moreover, the 16S rRNA gene sequencing identified as the dominant bacterium in the seawater, which changed to Pseudomonas and after the fresh water transfer. The alpha diversity analysis suggested that the gill bacterial diversity was lower in the fresh water transferred group. The KEGG and MetaCyc analysis further predicted the alteration of the glycosaminoglycan and chitin metabolisms in the gill bacteria. Collectively, the common glycosaminoglycan and chitin pathways in both the gill cells and gill microbiota suggest the host-bacterium interaction in gill facilitates the fresh water acclimation. This is the first study using the transcriptome and 16S rRNA gene sequencing to report the hypotonic responsive genes in gill cells and the compositions of gill microbiota in marine medaka. The overlapped glycosaminoglycan- and chitin-related pathways suggest host-bacterium interaction in fish gill during osmotic stress.
鱼类一直面临着渗透压的挑战，而鱼类的鳃是首先感知和应对外界渗透压变化的组织。然而，人们对于鱼类鳃微生物组如何响应渗透压变化及其潜在的宿主-细菌关系的理解还很有限。本研究的目的是通过转录组测序和 16S rRNA 基因测序，确定鳃细胞中对低渗环境有反应的基因，并分析淡水转移实验后鳃微生物组群落的变化。转录组测序结果显示，淡水转移后，鳃细胞中有 1034 个差异表达基因（DEGs），如水通道蛋白和钠钾氯共转运体。GO 和 KEGG 分析进一步强调了鳃中的类固醇生物合成和糖胺聚糖生物合成途径。此外，16S rRNA 基因测序结果显示，在海水中占优势的细菌是 ，而在淡水转移后，优势细菌变为 和 Pseudomonas。α多样性分析表明，淡水转移组的鳃细菌多样性较低。KEGG 和 MetaCyc 分析进一步预测了鳃细菌中糖胺聚糖和几丁质代谢的变化。总之，鳃细胞和鳃微生物组中共同的糖胺聚糖和几丁质代谢途径表明，鳃中的宿主-细菌相互作用有助于鱼类适应淡水环境。这是首次使用转录组和 16S rRNA 基因测序来报告鱼类鳃细胞中对低渗环境有反应的基因和海洋鲈形目鱼类鳃微生物组的组成。重叠的糖胺聚糖和几丁质相关途径表明，在渗透压应激下，鱼类鳃中的宿主-细菌相互作用。
