Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China.
Guangdong Provincial Key Laboratory of Fishery Ecology and Environment, South China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China.
Sci Total Environ. 2020 May 15;717:137048. doi: 10.1016/j.scitotenv.2020.137048. Epub 2020 Jan 31.
Algicidal behavior is a common interaction between marine microalgae and bacteria, especially in the dissipation phase of algal blooms. The marine bacterium Halobacillus sp. P1 was previously isolated and exhibits high algicidal activity against the diatom Skeletonema costatum. However, little is known about the mechanism underlying this algicidal process. Here, a tandem mass tag (TMT)-based proteomic approach was coupled with physiological analysis to investigate the cellular responses of S. costatum when treated with P1 culture supernatant. Among the 4582 proteins identified, 82 and 437 proteins were differentially expressed after treatment for 12 and 24 h, respectively. The proteomic results were in accordance with the results of verification by parallel reaction monitoring (PRM) assays. Proteins involved in reactive oxygen species scavenging, protein degradation and transport were upregulated, while proteins participating in nitrogen metabolism, protein translation, photosynthetic pigment biosynthesis and cell cycle regulation were significantly downregulated (p-value ≤0.05), corresponding to the increasing malondialdehyde content and the decreasing nitrogen, protein and chlorophyll a contents. A nutrient competitive relationship might exist between the bacterium P1 and S. costatum, and the inhibition of nitrogen metabolism by the P1 culture supernatant might be the key lethal factor that results in the dysfunction of S. costatum metabolism. Our study sheds light on the algicidal mechanism of P1 at the molecular level and provides new insights into algae-bacteria interactions.
杀菌行为是海洋微藻和细菌之间的一种常见相互作用，特别是在藻华的消散阶段。先前分离出的海洋细菌 Halobacillus sp. P1 对硅藻 Skeletonema costatum 具有很高的杀菌活性。然而，对于这种杀菌过程的机制知之甚少。在这里，采用串联质量标签（TMT）的蛋白质组学方法结合生理分析，研究了 P1 培养上清液处理后 S. costatum 的细胞反应。在鉴定的 4582 种蛋白质中，分别有 82 种和 437 种蛋白质在处理 12 和 24 小时后差异表达。蛋白质组学结果与平行反应监测 (PRM) 测定的验证结果一致。参与活性氧清除、蛋白质降解和运输的蛋白质上调，而参与氮代谢、蛋白质翻译、光合色素生物合成和细胞周期调节的蛋白质显著下调（p 值≤0.05），对应于丙二醛含量增加和氮、蛋白质和叶绿素 a 含量减少。细菌 P1 和 S. costatum 之间可能存在营养竞争关系，P1 培养上清液对氮代谢的抑制可能是导致 S. costatum 代谢功能障碍的关键致死因素。我们的研究从分子水平揭示了 P1 的杀菌机制，并为藻类-细菌相互作用提供了新的见解。
