Exotic invasive plants have been reported to alter the soil microbial community composition and function in order to facilitate their further invasion. These changes in the soil microbiome could be influenced also by the characteristics of the soil and sites. We hypothesised that (i) the invasion of Mediterranean semiarid ecosystems by the woody shrub Nicotiana glauca (tree tobacco) would promote a specific rhizosphere microbial community with particular functions and (ii) the rhizosphere microbial community associated with the invasive plant would be independent of the edaphic characteristics of the invaded site. We tested these hypotheses by comparing the rhizosphere microbial community of N. glauca with that of the native plant community at four sites covering a broad range of distinctive edaphic characteristics, including two human-disturbed environments and two naturally harsh Mediterranean environments (one saline and one gypsum soil). The soil microbial community composition was analysed using Illumina MiSeq sequencing and the rhizosphere microbial function was predicted by PICRUSt and FUNGuild. Our results suggest that the composition of the rhizosphere bacterial and fungal communities differed between N. glauca and the dominant native plant species and according to the soil characteristics. The metabolic functions of indicator taxa also differed between the invader and the dominant native plant species. In particular, the functions involved in the metabolism of carbon (C) and sulphur (S) compounds were overrepresented in the rhizosphere community of the invader. In conclusion, invasive N. glauca shifts the soil microbial community composition and its function related to C and S cycling in semiarid Mediterranean environments, including soils affected by salinity and gypsum.

据报道，外来入侵植物会改变土壤微生物群落的组成和功能，以促进其进一步入侵。土壤微生物组的这些变化也可能受到土壤和场所特性的影响。我们假设（i）木本灌木烟草（Nicotiana glauca）入侵地中海半干旱生态系统将促进具有特定功能的特定根际微生物群落，并且（ii）与入侵植物相关的根际微生物群落将独立于入侵部位的前卫特征。我们通过比较青冈猪笼草的根际微生物群落来检验这些假设与原生植物群落的分布在四个地点，涵盖了广泛的独特的埃及特色，包括两种人为干扰的环境和两种自然恶劣的地中海环境（一种盐水和一种石膏土壤）。使用Illumina MiSeq测序分析土壤微生物群落组成，并通过PICRUSt和FUNGuild预测根际微生物功能。我们的结果表明，青冈猪笼草的根际细菌和真菌群落组成不同以及主要的本地植物物种，并根据土壤特征而定。指示生物群的代谢功能在入侵者和优势原生植物物种之间也有所不同。尤其是，碳（C）和硫（S）化合物代谢所涉及的功能在入侵者的根际群落中被过度代表。总之，入侵性青冈猪笼草改变了地中海半干旱环境中土壤微生物群落组成及其与碳和硫循环相关的功能，包括受盐碱和石膏影响的土壤。