PREMISE There is growing recognition that intraspecific genetic variation in plants can influence associated soil microbial communities, but the functional bridges linking plant genotype with microbial community structure are not well understood. This deficit is due in part to a prevailing focus on characterizing relationships between microbial communities and functional trait variation among plant species or across plant communities, rather than within a single species. METHODS We examined whether and how spatiotemporal variation in salt marsh rhizosphere microbial communities reflect plant provenance (genotypic variation) and associated trait variation within an ecosystem engineer, Spartina alterniflora. We planted S. alterniflora from four genetically distinct source populations in replicate sets of experimental plots across a shoreline in southeastern Louisiana, USA. After 2 years, we measured functional plant traits and profiled microbial communities. RESULTS Bacterial and fungal α-diversity and richness were significantly higher in winter than in summer and corresponded to plant trait variation associated with provenance. Notably, 20% of the variation in fungal community composition was explained by trait differences while bacterial community structure did not reflect plant provenance or trait variation. However, evidence was found suggesting that bacterial communities are indirectly shaped by the influence of plant provenance on soil physicochemical properties. CONCLUSIONS This study illustrates that intraspecific genetic and corresponding trait variation in an ecosystem engineer can shape rhizosphere microbial communities, with fungal communities being more responsive than bacteria to the influence of plant provenance and associated trait variation. Our results highlight the potential relevance of plant intraspecific variation in plant-microbe-soil feedbacks shaping naturally depauperate ecosystems like salt marshes.

中文翻译：

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根际微生物群落反映了盐沼生态系统工程师的基因型和性状变异

前提 越来越多的人认识到植物的种内遗传变异会影响相关的土壤微生物群落，但连接植物基因型与微生物群落结构的功能桥梁尚不清楚。这种缺陷部分是由于普遍关注表征微生物群落与植物物种之间或跨植物群落的功能性状变异之间的关系，而不是在单个物种内。方法我们研究了盐沼根际微生物群落的时空变化是否以及如何反映生态系统工程师互花米草内的植物来源（基因型变异）和相关性状变异。我们种了 S。来自美国路易斯安那州东南部海岸线的一组重复实验地块中来自四个遗传不同来源种群的互花米草。2 年后，我们测量了功能性植物性状并分析了微生物群落。结果冬季细菌和真菌α-多样性和丰富度显着高于夏季，并且与与种源相关的植物性状变异相对应。值得注意的是，真菌群落组成的 20% 变化是由性状差异解释的，而细菌群落结构并未反映植物来源或性状变化。然而，有证据表明细菌群落是由植物来源对土壤理化特性的影响间接形成的。结论 本研究表明，生态系统工程师的种内遗传和相应性状变异可以塑造根际微生物群落，真菌群落对植物来源和相关性状变异的影响比细菌更敏感。我们的结果强调了植物-微生物-土壤反馈中植物种内变异的潜在相关性，这些反馈塑造了盐沼等自然枯竭的生态系统。