Department of Earth & Environmental Science, The University of Michigan, 1100 N. University Building, 1100 N. University Avenue, Ann Arbor, MI, 48109, USA.
Department of Chemical Engineering, The University of Michigan, NCRC, 2800 Plymouth Rd., Ann Abor, MI, 48109, USA.
Environ Microbiol. 2021 Jun;23(6):3020-3036. doi: 10.1111/1462-2920.15514. Epub 2021 Apr 21.
Interactions between bacteria and phytoplankton in the phycosphere have impacts at the scale of whole ecosystems, including the development of harmful algal blooms. The cyanobacterium Microcystis causes toxic blooms that threaten freshwater ecosystems and human health globally. Microcystis grows in colonies that harbour dense assemblages of other bacteria, yet the taxonomic composition of these phycosphere communities and the nature of their interactions with Microcystis are not well characterized. To identify the taxa and compositional variance within Microcystis phycosphere communities, we performed 16S rRNA V4 region amplicon sequencing on individual Microcystis colonies collected biweekly via high-throughput droplet encapsulation during a western Lake Erie cyanobacterial bloom. The Microcystis phycosphere communities were distinct from microbial communities in whole water and bulk phytoplankton seston in western Lake Erie but lacked 'core' taxa found across all colonies. However, dissimilarity in phycosphere community composition correlated with sampling date and the Microcystis 16S rRNA oligotype. Several taxa in the phycosphere were specific to and conserved with Microcystis of a single oligotype or sampling date. Together, this suggests that physiological differences between Microcystis strains, temporal changes in strain phenotypes, and the composition of seeding communities may impact community composition of the Microcystis phycosphere.
在藻球体内，细菌和浮游植物之间的相互作用会对整个生态系统产生影响，包括有害藻类水华的发展。蓝藻微囊藻会引发有毒水华，威胁着全球的淡水生态系统和人类健康。微囊藻以密集的细菌群落形式生长，但这些藻球体内群落的分类组成及其与微囊藻的相互作用性质尚不清楚。为了确定微囊藻藻球体内群落的分类组成和结构变化，我们对在西伊利湖蓝藻水华期间通过高通量液滴包封法每周两次采集的单个微囊藻集落进行了 16S rRNA V4 区扩增子测序。微囊藻藻球体内群落与西伊利湖全水体和浮游植物整体悬浮物中的微生物群落不同，但缺乏所有集落中都存在的“核心”分类群。然而，藻球体内群落组成的差异与采样日期和微囊藻 16S rRNA 寡型有关。藻球体内的几个分类群是特定于单一寡型或采样日期的微囊藻的，并具有保守性。综上所述，这表明微囊藻菌株之间的生理差异、菌株表型的时间变化以及接种群落的组成可能会影响微囊藻藻球体内群落的组成。
