The picture emerging from the rapidly growing literature on host-associated microbiota is that host traits and fitness often depend on interactive effects of host genotype, microbiota, and abiotic environment. However, testing interactive effects typically requires large, multi-factorial experiments and thus remains challenging in many systems. Furthermore, most studies of plant microbiomes focus on terrestrial hosts and microbes. Aquatic habitats may confer unique properties to microbiomes. We grew different populations of duckweed (Lemna minor), a floating aquatic plant, in three microbial treatments (adding no, "home", or "away" microbes) at two levels of zinc, a common water contaminant in urban areas, and measured both plant and microbial performance. Thus, we simultaneously manipulated plant source population, microbial community, and abiotic environment. We found strong effects of plant source, microbial treatment, and zinc on duckweed and microbial growth, with significant variation among duckweed genotypes and microbial communities. However, we found little evidence of interactive effects: zinc did not alter effects of host genotype or microbial community, and host genotype did not alter effects of microbial communities. Despite strong positive correlations between duckweed and microbe growth, zinc consistently decreased plant growth, but increased microbial growth. Furthermore, as in recent studies of terrestrial plants, microbial interactions altered a duckweed phenotype (frond aggregation). Our results suggest that duckweed source population, associated microbiome, and contaminant environment should all be considered for duckweed applications, such as phytoremediation. Lastly, we propose that duckweed microbes offer a robust experimental system for study of host-microbiota interactions under a range of environmental stresses.

中文翻译：

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Duckweed Lemna未成年人在植物种群，微生物和环境中的互惠结局。

迅速增长的有关寄主相关微生物群的文献中出现的图片是寄主的性状和适应性通常取决于寄主基因型，微生物群和非生物环境的相互作用。但是，测试交互效果通常需要进行大型的多因素实验，因此在许多系统中仍然具有挑战性。此外，大多数植物微生物群的研究都集中在陆地宿主和微生物上。水生生境可能赋予微生物群落独特的特性。我们使用三种微生物处理方法（不添加，“在家”或“离开”的微生物）以两种锌含量（市区常见的水污染物）种植了浮萍（浮游水生植物）的不同种群浮萍，并进行了测量植物和微生物的性能。因此，我们同时操纵了植物来源种群，微生物群落和非生物环境。我们发现植物来源，微生物处理和锌对浮萍和微生物生长的强大影响，浮萍基因型和微生物群落之间存在显着差异。但是，我们几乎没有发现相互作用的证据：锌不会改变宿主基因型或微生物群落的作用，而宿主基因型也不会改变微生物群落的作用。尽管浮萍与微生物的生长之间具有很强的正相关性，但锌一直在降低植物的生长，但增加了微生物的生长。此外，正如最近对陆地植物的研究一样，微生物相互作用改变了浮萍的表型（前聚集）。我们的结果表明，浮萍应用中应考虑浮萍来源种群，相关微生物组和污染环境，例如植物修复。最后，我们提出浮萍微生物提供了一个强大的实验系统，用于研究在一系列环境压力下宿主-微生物的相互作用。