Weigel Brooke L, Pfister Catherine A
Committee on Evolutionary Biology, University of Chicago, Chicago, IL, United States.
Department of Ecology and Evolution, University of Chicago, Chicago, IL, United States.
Front Microbiol. 2019 Feb 26;10:346. doi: 10.3389/fmicb.2019.00346. eCollection 2019.
Canopy-forming kelps create underwater forests that are among the most productive marine ecosystems. On the Pacific coast of North America, two canopy-forming kelps with contrasting life histories co-occur; , a perennial species, and , an annual species. Kelp blade-associated microbes were sampled from 12 locations across a spatial gradient in Washington, United States, from the outer Pacific Coast to Puget Sound. Microbial communities were characterized using next-generation Illumina sequencing of 16S rRNA genes. At higher taxonomic levels (bacterial phylum and class), canopy-forming kelps hosted remarkably similar microbial communities, but at the amplicon sequence variant level, microbial communities on and were host-specific and distinct from free-living bacteria in the surrounding seawater. Microbial communities associated with blades of each kelp species displayed significant geographic variation. The microbiome of changed along the spatial gradient and was significantly correlated to salinity, with outer Pacific coast sites enriched in (family ) and ( sp.), and southern Puget Sound sites enriched in (family ). We also examined microbial community development and succession on meristematic and apical blade tissues throughout the summer growing season on Tatoosh Island, WA. Across all dates, microbial communities were less diverse on younger, meristematic blade tissue compared to the older, apical tissues. In addition, phylogenetic relatedness among microbial taxa increased from meristematic to apical blade tissues, suggesting that the addition of microbial taxa to the community was a non-random process that selected for certain phylogenetic groups of microbes. Microbial communities on older, apical tissues displayed significant temporal variation throughout the summer and microbial taxa that were differentially abundant over time displayed clear patterns of community succession. Overall, we report that host species identity, geographic location, and blade tissue age shape the microbial communities on canopy-forming kelps.
形成冠层的海带创造了水下森林，这些水下森林是生产力最高的海洋生态系统之一。在北美太平洋海岸，两种具有不同生活史的形成冠层的海带同时存在；一种是多年生物种，另一种是一年生物种。从美国华盛顿州从外太平洋海岸到普吉特海湾的空间梯度上的12个地点采集了与海带叶片相关的微生物。使用16S rRNA基因的下一代Illumina测序对微生物群落进行了表征。在较高的分类水平（细菌门和纲）上，形成冠层的海带拥有非常相似的微生物群落，但在扩增子序列变体水平上，两种海带的微生物群落具有宿主特异性，并且与周围海水中的自由生活细菌不同。与每种海带物种叶片相关的微生物群落表现出显著的地理变异。某一种海带的微生物组沿空间梯度变化，并且与盐度显著相关，外太平洋海岸的地点富含某一菌科和某一菌属，而普吉特海湾南部的地点富含另一菌科。我们还研究了华盛顿州塔托什岛整个夏季生长季节分生组织和顶端叶片组织上微生物群落的发育和演替。在所有日期中，与较老的顶端组织相比，较年轻的分生组织叶片组织上的微生物群落多样性较低。此外，微生物分类群之间的系统发育相关性从分生组织叶片组织到顶端叶片组织增加，这表明微生物分类群添加到群落中是一个非随机过程，该过程选择了某些系统发育组的微生物。在整个夏季，较老的顶端组织上的微生物群落表现出显著的时间变化，并且随时间差异丰富的微生物分类群显示出明显的群落演替模式。总体而言，我们报告宿主物种身份、地理位置和叶片组织年龄塑造了形成冠层的海带的微生物群落。
