Abstract：
Zostera marina (seagrass) is a coastal marine angiosperm that sustains a diverse and productive ecosystem. Seagrass-associated microbiota support host health, yet the ecological processes that maintain biodiversity and stability of the seagrass leaf microbiota are poorly understood. We tested two hypotheses: (1) Microbes select seagrass leaves as habitat such that they consistently host distinct microbiota and/or core taxa in comparison to nearby substrates, and (2) seagrass leaf microbiota are stable once established and are resistant to change when transplanted to a novel environment. We reciprocally transplanted replicate seagrass shoots (natural and surface sterilized/dead tissue treatments) among four meadows with different environmental conditions and deployed artificial seagrass treatments in all four meadows. At the end of the 5-day experiment, the established microbiota on natural seagrass partially turned over to resemble microbial communities in the novel meadow, and all experimental treatments hosted distinct surface microbiota. We consistently found that natural and sterilized/dead seagrass hosted more methanol-utilizing bacteria compared to artificial seagrass and water, suggesting that seagrass core microbiota are shaped by taxa that metabolize seagrass exudates coupled with minor roles for host microbial defence and/or host-directed recruitment. We found evidence that the local environment strongly influenced the seagrass leaf microbiota in natural meadows and that transplant location explained more variation than experimental treatment. Transplanting resulted in high turnover and variability of the seagrass leaf microbiota, suggesting that it is flexibly assembled in a wide array of environmental conditions which may contribute to resilience of seagrass in future climate change scenarios.
摘要：
Zosteramarina（海草）是沿海海洋被子植物，维持着多样化和多产的生态系统。海草相关微生物群支持宿主健康，然而，对维持生物多样性和海草叶片微生物群稳定性的生态过程知之甚少。我们测试了两个假设：（1）微生物选择海草叶作为栖息地，因此与附近的底物相比，它们始终承载不同的微生物群和/或核心分类群，和（2）海草叶片微生物群一旦建立是稳定的，并且在移植到新环境中时对变化具有抗性。我们在具有不同环境条件的四个草甸中相互移植了复制的海草芽（自然和表面灭菌/死亡组织处理），并在所有四个草甸中进行了人工海草处理。在为期5天的实验结束时,在天然海草上建立的微生物群部分地转变为类似于新型草甸中的微生物群落，所有实验处理都有不同的表面微生物群。我们一致发现，与人造海草和水相比，天然和灭菌/死亡的海草拥有更多的甲醇利用细菌，这表明海草核心微生物群是由代谢海草分泌物的类群形成的，再加上宿主微生物防御和/或宿主定向招募的次要作用。我们发现有证据表明，当地环境强烈影响了天然草甸中的海草叶片微生物群，并且移植位置比实验处理解释了更多的变化。移栽导致海草叶片微生物群的高周转和变异性，这表明它是在广泛的环境条件下灵活组装的，这可能有助于海草在未来气候变化情景中的复原力。
