ABSTRACT

Smooth cordgrass, Spartina alterniflora, dominates salt marshes on the east coast of the United States. While the physicochemical cues affecting S. alterniflora productivity have been studied intensively, the role of plant–microbe interactions in ecosystem functioning remains poorly understood. Thus, in this study, the effects of S. alterniflora phenotype on the composition of archaeal, bacterial, diazotrophic and fungal communities were investigated. Overall, prokaryotic communities were more diverse and bacteria were more abundant in the areas colonized by the tall plant phenotype in comparison to those of short plant phenotype. Diazotrophic methanogens (Methanomicrobia) preferentially colonized the area of the short plant phenotype. Putative iron-oxidizing Zetaproteobacteria and sulfur-oxidizing Campylobacteria were identified as indicator species in the rhizosphere of tall and short plant phenotypes, respectively. Finally, while diazotrophic populations shaped microbial interactions in the areas colonized by the tall plant phenotype, fungal populations filled this role in the areas occupied by the short plant phenotype. The results here demonstrate that S. alterniflora phenotype and proximity to the root zone are selective forces dictating microbial community assembly. Results further reveal that reduction–oxidation chemistry is a major factor driving the selection of belowground microbial populations in salt marsh habitats.

中文翻译：

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阐明与美国乔治亚州斯基德威岛的盐沼中互花米草表型相关的根际微生物组

摘要

光滑的草苔，互花米草（Spartina alterniflora）在美国东海岸的盐沼中占主导地位。尽管已经深入研究了影响互生链球菌生产力的理化线索，但对植物与微生物相互作用在生态系统功能中的作用仍知之甚少。因此，在这项研究中，研究了互花米草表型对古细菌，细菌，重氮营养和真菌群落组成的影响。总体而言，与短植物表型相比，高植物表型定植的区域中原核生物群落更加多样化，细菌也更加丰富。重氮营养型产甲烷菌（Methanomicrobia）优先定植在短植表型区域。推定的铁氧化Zetaproteobacteria细菌和硫氧化Campylobacteria被确定为高和短植物表型的根际中的指示物种。最后，虽然重营养种群在高植物表型所定植的区域内形成微生物相互作用，但真菌种群在短植物表型所占的区域内发挥了这种作用。这里的结果表明互花米草表型和与根区的接近是决定微生物群落装配的选择性力。结果进一步表明，还原-氧化化学是驱动盐沼栖息地地下微生物种群选择的主要因素。