Marine Ecology and Human Factors Assessment Technical Innovation Center of Natural Resources Ministry, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China; Shenzhen Key Laboratory of Advanced Technology for Marine Ecology, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, Guangdong Province, PR China.
School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai 264209, Shandong Province, PR China.
Sci Total Environ. 2024 Oct 10;946:174134. doi: 10.1016/j.scitotenv.2024.174134. Epub 2024 Jun 21.
Phaeocystis globosa is among the dominant microalgae associated with harmful algal blooms. P. globosa has a polymorphic life cycle and its ecological success has been attributed to algal colony formation, however, few studies have assessed differences in microbial communities and their functional profiles between intra- and extra-colonies during P. globosa blooms. To address this, environmental and metagenomics tools were used to conduct a time-series analysis of the bacterial composition and metabolic characteristics of intra- and extra-colonies during a natural P. globosa bloom. The results show that bacterial composition, biodiversity, and network interactions differed significantly between intra- and extra-colonies. Dominant extra-colonial bacteria were Bacteroidia and Saccharimonadis, while dominant intra-colonial bacteria included Alphaproteobacteria and Gammaproteobacteria. Despite the lower richness and diversity observed in the intra-colonial bacterial community, relative to extra-colonies, the complexity and interconnectedness of the intra-colonial networks were higher. Regarding bacterial function, more functional genes were enriched in substance metabolism (polysaccharides, iron element and dimethylsulfoniopropionate) and signal communication (quorum sensing, indoleacetic acid-IAA) pathways in intra- than in extra-colonies. Conceptual model construction showed that microbial cooperative synthesis of ammonium, vitamin B, IAA, and siderophores were strongly related to the P. globosa bloom, particularly in the intra-colonial environment. Overall, our data highlight the differences in bacterial structure and functions within and outside the colony during P. globosa blooms. These findings represent fundamental information indicating that phenotypic heterogeneity is a selective strategy that improves microbial population competitiveness and environmental adaptation, benefiting P. globosa bloom formation and persistence.
微囊藻是与有害藻华有关的优势微藻之一。微囊藻具有多态生命周期，其生态成功归因于藻群形成，但很少有研究评估在微囊藻藻华期间藻群内和藻群间微生物群落及其功能特征的差异。为了解决这个问题，使用环境和宏基因组学工具对自然微囊藻藻华期间藻群内和藻群间的细菌组成和代谢特征进行了时间序列分析。结果表明，藻群内和藻群间的细菌组成、生物多样性和网络相互作用存在显著差异。优势外生菌为拟杆菌门和 Saccharimonadis，而优势内生菌包括α变形菌纲和γ变形菌纲。尽管与藻群外相比，藻群内的细菌群落丰富度和多样性较低，但藻群内的网络复杂性和相互连接性较高。关于细菌功能，物质代谢（多糖、铁元素和二甲基亚砜丙酸酯）和信号通讯（群体感应、吲哚乙酸-IAA）途径中富集了更多的功能基因。概念模型构建表明，微生物对铵、维生素 B、IAA 和铁载体的协同合成与微囊藻藻华密切相关，特别是在藻群内环境中。总的来说，我们的数据强调了微囊藻藻华期间藻群内和藻群间细菌结构和功能的差异。这些发现代表了基本信息，表明表型异质性是一种选择性策略，可提高微生物种群竞争力和环境适应性，有利于微囊藻藻华的形成和持续。
