BACKGROUND Given their adaptation to nutrient-poor and drought environments, cycads are vital models for plant-microbiome interaction research because they are likely to host an important reservoir of beneficial microbes that may support cycad survival. However, a comprehensive understanding of the diversity and community composition of microbiome associated with different plant compartments as well as bulk soils of cycad species remains elusive. METHOD An extensive investigation of species diversity and community composition of bacterial and fungal microbiome in roots, seeds, unfertilized seeds, ovules, pollens, and soils of Cycas panzhihuaensis L. Zhou & S. Y. Yang has been conducted by high-through sequencing technology. Moreover, principal component analysis (PCA), hierarchical cluster analysis (HCA), and heatmap analysis were applied to test the niche-specific effect and biogeography factor among different sample types of this cycad species. RESULTS Highly diverse microbiota and significant variation of community structure were found among different compartments of C. panzhihuaensis. Soils exhibited a remarkable differentiation of bacterial community composition compared to the other five plant organs as revealed by PCA, HCA, and heatmap analyses. Different compartments possessed unique core microbial taxa with Pseudomonadaceae and Nectriaceae shared among them. According to the indicator species analysis, there was almost no differentiation of dominant microbiomes with regard to the geography of the host cycad. Two main transmission models existed in the C. panzhihuaensis. CONCLUSIONS Each sample type represented a unique niche and hosted a niche-specific core microbial taxa. Contrary to previous surveys, biogeography hardly exerted impact on microbial community variation in this study. The majority of the cycad-associated microbes were horizontally derived from soils and/or air environments with the rest vertically inherited from maternal plants via seeds. This study offers a robust knowledge of plant-microbiome interaction across various plant compartments and soils and lends guidelines to the investigation of adaptation mechanism of cycads in arid and nutrient-poor environments as well as their evolutionary conservation.

中文翻译：

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生态位分化而不是生物地理学决定了攀枝花苏铁属微生物组的多样性和组成。

背景技术由于苏铁适合于营养不良和干旱的环境，因此苏铁是植物-微生物组相互作用研究的重要模型，因为它们可能拥有重要的有益微生物库，可以支持苏铁的生存。但是，对与不同植物区隔以及苏铁物种的大量土壤相关的微生物组的多样性和群落组成的全面了解仍然难以捉摸。方法采用高通量测序技术对攀枝花苏铁属的根，种子，未受精种子，胚珠，花粉和土壤中细菌和真菌微生物群的物种多样性和群落组成进行了广泛的调查。此外，主成分分析（PCA），层次聚类分析（HCA），运用热图分析对苏铁科植物不同样本类型的生态位效应和生物地理因子进行了测试。结果在攀枝花不同隔间中发现了高度多样化的微生物群和群落结构的显着变化。PCA，HCA和热图分析表明，与其他五个植物器官相比，土壤表现出了显着的细菌群落组成差异。不同的隔室具有独特的核心微生物分类群，其中假单胞菌科和油桃科共享。根据指示物物种分析，就苏铁的地理而言，优势微生物群落几乎没有分化。攀枝花中华exist存在两种主要的传播模式。结论每种样品类型代表一个独特的生态位，并具有一个生态位特异性的核心微生物分类群。与以前的调查相反，在这项研究中，生物地理学几乎对微生物群落的变化没有影响。与苏铁相关的大多数微生物是从土壤和/或空气环境中水平衍生而来的，其余的则是通过种子从母本植物中垂直遗传的。这项研究提供了在各种植物区隔和土壤之间植物-微生物组相互作用的扎实知识，并为研究苏铁在干旱和营养缺乏的环境中的适应机制及其进化保护提供了指导。苏铁相关的微生物大多数是水平地从土壤和/或空气环境中衍生的，其余的是垂直地从母本植物中通过种子遗传的。这项研究提供了在各种植物区隔和土壤之间植物-微生物组相互作用的扎实知识，并为研究苏铁在干旱和营养缺乏的环境中的适应机制及其进化保护提供了指导。与苏铁相关的大多数微生物是从土壤和/或空气环境中水平衍生而来的，其余的则是通过种子从母本植物中垂直遗传的。这项研究提供了在各种植物区隔和土壤之间植物-微生物组相互作用的扎实知识，并为研究苏铁在干旱和营养缺乏的环境中的适应机制及其进化保护提供了指导。