Table_4_Proteomic Response to Environmental Stresses in the Stolon of a Highly Invasive Fouling Ascidian.XLS

Ascidians, particularly those highly invasive ones, are typical fouling organisms to cause significantly negative ecological and economic influence in coastal ecosystems. Stolon, which is the unique structure of some solitary ascidians to complete the essential process of adhesion, possesses extremely high tolerance to environmental stresses during biofouling and invasions. However, the mechanisms underlying environmental tolerance remain largely unknown. Here, we used the quantitative proteomics technology, isobaric tags for relative and absolute quantitation (iTRAQ), to investigate the molecular response to environmental challenges (temperature and salinity) in the stolon of a highly invasive fouling ascidian, Ciona robusta. When compared with the control, a total of 75, 86, 123, and 83 differential abundance proteins were identified under low salinity, high salinity, low temperature, and high temperature stress, respectively. Bioinformatic analyses uncovered the key pathways under both temperature and salinity stresses, including “cytoskeleton,” “signal transduction,” and “posttranslational modification,” which were involved in stolon structure stability, protein synthesis, and stress response activation. Under the low salinity stress, the “extracellular matrix” pathway was identified to play a crucial role by regulating cell signal transduction and protein synthesis. To deal with the high salinity stress, stolon could store more energy by activating “carbohydrate/lipid transport” and “catabolism” pathways. The energy generated by “lipid metabolism” pathway might be beneficial to resist the low temperature stress. The upregulation of “cell cycle” pathway could inhibit cell growth, thus helping stolon conserve more energy against the high temperature stress. Our results here provide valuable references of candidate pathways and associated genes for studying mechanisms of harsh environmental adaptation and developing antifouling strategies in marine and coastal ecosystems.

海鞘类生物，尤其是那些高度入侵性的种类，通常是典型的附着生物，会在沿海生态系统中对生态和经济产生显著的负面影响。茎枝，作为某些独居海鞘完成附着这一基本过程的独特结构，在生物附着和入侵过程中表现出极高的环境压力耐受性。然而，环境耐受性的潜在机制仍鲜为人知。在本研究中，我们利用定量蛋白质组学技术，即同位素标记相对和绝对定量（iTRAQ），探究了高度入侵性附着海鞘Ciona robusta的茎枝对环境挑战（温度和盐度）的分子响应。与对照相比，在低盐度、高盐度、低温和高温胁迫下，分别鉴定出75、86、123和83种差异丰度蛋白。生物信息学分析揭示了温度和盐度胁迫下的关键通路，包括“细胞骨架”、“信号转导”和“翻译后修饰”，这些通路与茎枝结构稳定性、蛋白质合成和胁迫响应激活相关。在低盐度胁迫下，“细胞外基质”通路被证实发挥着至关重要的作用，通过调节细胞信号转导和蛋白质合成。为了应对高盐度胁迫，茎枝可以通过激活“碳水化合物/脂质运输”和“分解代谢”通路来储存更多能量。由“脂质代谢”通路产生的能量可能有助于抵抗低温胁迫。上调“细胞周期”通路可以抑制细胞生长，从而帮助茎枝在高温胁迫下节约更多能量。本研究结果为研究恶劣环境适应机制以及开发海洋和沿海生态系统中的防污策略提供了有价值的候选通路和关联基因参考。