CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
Int J Environ Res Public Health. 2022 Apr 7;19(8):4446. doi: 10.3390/ijerph19084446.
Interactions between algae and bacteria represent an important inter-organism association in aquatic environments, which often have cascading bottom-up influences on ecosystem-scale processes. Despite the increasing recognition of linkages between bacterioplankton and dynamics of dinoflagellate blooms in the field, knowledge about the forms and functions of dinoflagellate-bacteria associations remains elusive, mainly due to the ephemeral and variable conditions in the field. In this study, we characterized the bacterial community associated with laboratory cultures of 144 harmful algal strains, including 130 dinoflagellates (covering all major taxonomic orders of dinoflagellates) and 14 non-dinoflagellates, via high-throughput sequencing for 16S rRNA gene amplicons. A total of 4577 features belonging to bacteria kingdom comprising of 24 phyla, 55 classes, 134 orders, 273 families, 716 genera, and 1104 species were recovered from the algal culture collection, and 3 phyla (Proteobacteria, Bacteroidetes, and Firmicutes) were universally present in all the culture samples. Bacterial communities in dinoflagellates cultures exhibited remarkable conservation across different algal strains, which were dominated by a relatively small number of taxa, most notably the -proteobacteria , and . Although the bacterial community composition between dinoflagellates and non-dinoflagellate groups did not show significant difference in general, dinoflagellates harbored a large number of unique features (up to 3811) with relatively low individual abundance and enriched in the potential methylotrophs While the bacterial assemblages associated with thecate and athecate dinoflagellates displayed no general difference in species composition and functional groups, athecate dinoflagellates appeared to accommodate more aerobic cellulolytic members of Actinobacteria, implying a more possible reliance on cellulose utilization as energy source. The extensive co-occurrence discovered here implied that the relationships between these algal species and the bacterial consortia could be viewed as either bilaterally beneficial (i.e., mutualism) or unilaterally beneficial at least to one party but virtually harmless to the other party (i.e., commensalism), whereas both scenarios support a long-term and stable co-existence rather than an exclusion of one or the other. Our results demonstrated that dinoflagellates-associated bacterial communities were similar in composition, with enrichment of potential uncultured methylotrophs to one-carbon compounds. This work enriches the knowledge about the fundamental functions of bacteria consortia associated with the phycospheres of dinoflagellates and other HABs-forming microalgae.
藻类和细菌之间的相互作用是水生环境中一种重要的种间关联，通常对生态系统尺度的过程具有级联的自上而下的影响。尽管越来越多的人认识到浮游细菌与甲藻赤潮动态之间的联系，但关于甲藻-细菌关联的形式和功能的知识仍然难以捉摸，这主要是由于野外条件的短暂性和可变性。在这项研究中，我们通过高通量测序对 16S rRNA 基因扩增子对来自实验室培养的 144 种有害藻类菌株（包括 130 种甲藻（涵盖甲藻的所有主要分类目）和 14 种非甲藻）的相关细菌群落进行了表征。从藻类培养物中回收了属于细菌界的 4577 个特征，包括 24 个门，55 个纲，134 个目，273 个科，716 个属和 1104 个种，并且 3 个门（变形菌门，拟杆菌门和厚壁菌门）普遍存在于所有培养样本中。甲藻培养物中的细菌群落具有显著的跨不同藻株的保守性，这些细菌群落主要由相对较少的类群组成，最显著的是α-变形菌纲和γ-变形菌纲。尽管甲藻和非甲藻组之间的细菌群落组成总体上没有显著差异，但甲藻却拥有大量独特的特征（多达 3811 个），其个体丰度相对较低，并富含潜在的甲基营养菌。虽然有囊和无囊甲藻的细菌组合在物种组成和功能群上没有差异，但无囊甲藻似乎容纳了更多好氧纤维素分解菌 actinobacteria，这意味着对纤维素的利用作为能源的依赖性可能更高。这里发现的广泛共存表明，这些藻类物种与细菌共生体之间的关系可以被视为双边互利（即共生）或至少对一方单方面有利而对另一方几乎无害（即共栖），而这两种情况都支持长期稳定的共存，而不是一方排斥另一方。我们的研究结果表明，甲藻相关细菌群落的组成相似，富含有可能利用单碳化合物的潜在未培养甲基营养菌。这项工作丰富了有关与甲藻和其他形成赤潮的微藻的噬菌球体相关的细菌共生体的基本功能的知识。
