|Place of Conferral||中国科学院海洋研究所|
|Keyword||深海化能生态系统 拟刺铠虾 极端环境适应 转录组 眼睛颜色表型|
Compared to shallow marine environments, deep-sea hydrothermal vent and cold seep environments are not only dark, high-pressure, low-oxygen and oligotrophic, but also rich in toxic substances such as methane, sulphur and hydrogen sulfide, etc., which are converted into biomass by chemoautotrophic microorganisms, sustaining the entire ecosystem. Despite sharing similar processes of chemosynthesis, deep-sea vents and seeps are assumed to different in tectonic settings and physicochemical properties. Nevertheless, animals have evolved a series of survival strategies to thrive in such extreme deep-sea environments. The munidopsid squat lobsters, Munidopsis lauensis and Munidopsis verrilli are among the dominant species in the benthic communities of deep-sea chemosynthetic ecosystems, and can serve as excellent materials for exploring the mechanisms underlying adaptation of macrofauna to deep-sea chemosynthetic extreme environments.
To providing insights into adaptations of munidopsid squat lobsters to deep-sea chemosynthetic environments, full-length transcriptomes of M. lauensis, M. verrilli and their shallow-sea relative Allogalathea elegans were generated using a combination of single-molecule real-time and Illumina RNA-seq technology. The analysis revealed a significant enrichment of immune-related pathways in the highly expressed genes of deep-sea squat lobsters. Gene family expansion analysis revealed that genes related to innate immune response, sulfur metabolism, antioxidant defense, and cold tolerance underwent significant expansion in deep-sea squat lobsters. Finally, positively selected genes identified in two deep-sea Munidopsis species were involved in immunity, detoxification and resistance to environmental stress. These genes may play important roles in the adaptation of munidopsid squat lobsters to deep-sea extreme environmental conditions, such as low temperature, complex microbial composition, high concentrations of hydrogen sulfide and heavy metals.
Considering the differences in tectonic settings and physicochemical properties between deep-sea vents and seeps, it is hypothesized that the local animals probably exhibited novel molecular features associated with adaptation to their respective habitats. In this study, comparative transcriptome analysis was applied to characterize gene expression profiles of hepatopancreas and muscles of M. lauensis from a methane seep in the South China Sea (CS) and a hydrothermal vent in the Manus back-arc Basin (HV). A heatmap based on the expression levels of 1,017 common differentially expressed transcripts (DETs) to hepatopancreas and muscle indicated remarkably different expression patterns between HV and CS lobsters regardless of sampled tissues, suggesting an environmentally mediated pattern of gene expression. Functional annotation and enrichment analyses indicated most of the shared DETs involved in detoxification, oxidative stress resistance and innate immune response were consistently up-regulated in HV lobsters. At the same time, there was clear evidence for the upregulation of genes associated with hydrogen sulfide (H2S) oxidation, endogenous H2S production and mitochondrial oxidative phosphorylation in HV lobsters. It is hypothesized that the M. lauensis may have adapted to different deep-sea chemosynthetic environments by regulating the expression patterns of key genes related to environmental adaptation. Moreover, overexpression of a battery of environmental response-related genes in HV might suggest hydrothermal vents as more extreme deepsea chemoautotrophic environments in comparison with cold seeps.
In deep-sea chemosynthetic environment, it is interesting to find orange-eye (OE) and white-eye (WE) phenotypes in some crustacean species. We performed a comparative transcriptome analysis to investigate the molecular basis for the formation of the two eye phenotypes of M. verrilli. Comparative transcriptome analysis revealed that the functions of many DETs between OE and WE were associated with biological processes such as innate immunity, antioxidation and detoxification. Of note, we found that 23 unigenes associated with ocular pigment synthesis were also significantly differentially expressed between OE and WE. A joint analysis of the eye transcriptomic data of Alvinocaris longirostris, which also has two eye color phenotypes, showed that the expression trends of key genes involved in immune, pteridine pigment synthesis pathways and the ommochrome biosynthesis pathway were consistent in the orange and white eyes of both deep-sea crustacean species. The underlying factors driving different eye color phenotype formation may be related with physical responses of M. verrilli to variable micro-environmental stressors in deep-sea chemosynthetic habitats,which in turn influence pigment synthesis in the eye.
In summary, this study provides the first comparative analysis of deep-sea munidopsid squat lobsters with their shallow-water relatives using second- and thirdgeneration transcriptome sequencing techniques. This study also represents a first step in understanding molecular basis of crustacean adaptation to different types of deep-sea chemosynthetic environments by investigating transcriptional profiling in multiple tissues. These results greatly expand our understanding of how microbenthic crustaceans adapt to deep-sea chemosynthetic extreme environments and respond to different vent and seep environments at the transcriptome level. Furthermore, we provide a preliminary investigation of the molecular basis of differences in the two eye color phenotypes of M. verrilli. In the present study, we enrich the transcriptome data of macrobenthic organisms inhabiting in deep-sea chemosynthetic environments. The results can also provide important datasets for studying adaptive evolution of crustaceans in deep-sea chemosynthetic ecosystems and exploring new genetic resources.
|MOST Discipline Catalogue||理学 ; 理学::海洋科学 ; 理学::生物学|
|闫晗. 拟刺铠虾对深海化能极端环境适应机制的转录组学解析[D]. 中国科学院海洋研究所. 中国科学院海洋研究所,2023.|
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