CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China.
Sci Total Environ. 2022 Sep 10;838(Pt 2):155985. doi: 10.1016/j.scitotenv.2022.155985. Epub 2022 May 18.
The harmful algal bloom (HAB) species Phaeocystis globosa is commonly observed in global temperate and tropical oceans, and colonies of P. globosa exhibit a dominant morphotype during blooms. The use of polyaluminium chloride modified clay (PAC-MC) is an effective mitigation strategy for P. globosa blooms. Although previous studies have found that PAC-MC can stimulate P. globosa colony formation at low concentrations and inhibit it at higher concentrations, the underlying mechanisms of these effects are poorly understood. Here, we comprehensively compared the physiochemical indices and transcriptomic response of residual P. globosa cells after treatment with two concentrations of PAC-MC. The results showed that PAC-MC induced oxidative stress, photosynthetic inhibition, and DNA damage in residual cells. Moreover, it could activate antioxidant responses and enhance the repair of photosynthetic structure and DNA damage in cells. The biosynthesis of polysaccharides was enhanced and genes associated with cell motility were down-regulated after treatment with PAC-MC, resulting in the accumulation of colonial matrixes. After treatment with a low concentration of PAC-MC (0.1 g/L), the residual cells were slightly stressed, including physical damage, oxidative stress and other damage, and polysaccharide synthesis was enhanced to promote colony formation to alleviate environmental stress. Moreover, the damage to residual cells was slight; thus, normal cell function provided abundant energy and matter for colony formation. After treatment with a high concentration of PAC-MC (0.5 g/L), the residual cells suffered severe damage, which disrupted normal physiological processes and inhibited cell proliferation and colony formation. The present study elucidated the concentration-dependent mechanism of PAC-MC affecting the formation of P. globosa colonies and provided a reference for the application of PAC-MC to control P. globosa blooms.
赤潮藻聚球藻是一种常见的全球性温带和热带海洋物种，其群体在赤潮发生时呈现出优势形态。聚合氯化铝改性黏土（PAC-MC）的使用是一种有效的聚球藻赤潮缓解策略。尽管先前的研究发现，PAC-MC 可以在低浓度下刺激聚球藻群体形成，并在高浓度下抑制其生长，但这些影响的潜在机制仍知之甚少。在这里，我们综合比较了两种浓度的 PAC-MC 处理后残留聚球藻细胞的理化指标和转录组响应。结果表明，PAC-MC 诱导了残留细胞的氧化应激、光合作用抑制和 DNA 损伤。此外，它可以激活抗氧化反应，增强细胞光合结构和 DNA 损伤的修复。多糖的生物合成增强，与细胞运动相关的基因下调，导致群体基质的积累。用低浓度 PAC-MC（0.1 g/L）处理后，残留细胞受到轻微胁迫，包括物理损伤、氧化应激等损伤，多糖合成增强，促进群体形成，以缓解环境胁迫。而且，残留细胞的损伤较轻；因此，正常细胞功能为群体形成提供了丰富的能量和物质。用高浓度 PAC-MC（0.5 g/L）处理后，残留细胞受到严重损伤，破坏了正常的生理过程，抑制了细胞增殖和群体形成。本研究阐明了 PAC-MC 影响聚球藻群体形成的浓度依赖性机制，为 PAC-MC 应用于控制聚球藻赤潮提供了参考。
