Table_5_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，尤其是那些极具侵略性的种类，是典型的附着生物，它们在沿海生态系统中对生态环境和经济效益产生了显著的负面影响。茎枝，某些独居海鞘独特的粘附结构，在生物附着和入侵过程中对环境压力具有极高的耐受性。然而，环境耐受性的潜在机制仍知之甚少。本研究中，我们运用定量蛋白质组学技术——同位素标记相对和绝对定量（iTRAQ），探究了高度侵略性附着海鞘Ciona robusta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、低温和高温压力下，分别鉴定出75、86、123和83种差异丰度蛋白质。生物信息学分析揭示了温度和盐度压力下的关键通路，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、蛋白质合成和压力响应激活相关。在低盐度压力下，“细胞外基质”通路被鉴定为通过调节细胞信号转导和蛋白质合成发挥关键作用。为了应对高盐度压力，茎枝通过激活“碳水化合物/脂质运输”和“分解代谢”通路储存更多能量。由“脂质代谢”通路产生的能量可能有助于抵抗低温压力。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压力下节约更多能量。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的防污策略提供了宝贵的候选通路和相关基因的参考。