Arid environments are defined by the lack of water availability, which is directly related to the mean annual precipitation (MAP), and high values of solar irradiation, which impacts the community composition of animals, plants, and the microbial structure of the soil. Recent advances in NGS technologies have expanded our ability to characterize microbiomes, allowing environmental microbiologists to explore the complete microbial structure. Intending to identify and describe the state-of-the-art of bacterial communities in arid soils at a global scale, and to address the effect that some environmental features may have on them, we performed a systematic review based on the PRISMA guideline. Using a combination of keywords, we identified a collection of 66 studies, including 327 sampled sites, reporting the arid soil bacterial community composition by 16S rDNA gene high-throughput sequencing. To identify factors that can modulate bacterial communities, we extracted the geographical, environmental, and physicochemical data. The results indicate that even though each sampled site was catalogued as arid, they show wide variability in altitude, mean annual temperature (MAT), soil pH and electric conductivity, within and between arid environments. We show that arid soils display a higher abundance of Actinobacteria and lower abundance of Proteobacteria, Cyanobacteria, and Planctomycetes, compared with non-arid soil microbiomes, revealing that microbial structure seems to be strongly modulated by MAP and MAT and not by pH in arid soils. We observed that environmental and physicochemical features were scarcely described among studies, hence, we propose a reporting guideline for further analysis, which will allow deepening the knowledge of the relationship between the microbiome and abiotic factors in arid soil. Finally, to understand the academic collaborations landscape, we developed an analysis of the author’s network, corroborating a low degree of connectivity and collaborations in this research topic. Considering that it is crucial to understand how microbial processes develop and change in arid soils, our analysis emphasizes the need to increase collaborations between research groups worldwide.

中文翻译：

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全球范围内来自干旱环境的微生物群落。系统的审查。

干旱环境是由于缺乏水资源而造成的，水资源的缺乏直接关系到年平均降水量（MAP）和太阳辐射的高值，这会影响动物，植物的群落组成以及土壤的微生物结构。NGS技术的最新进展扩展了我们表征微生物组的能力，使环境微生物学家能够探索完整的微生物结构。为了在全球范围内识别和描述干旱土壤中最新的细菌群落，并解决某些环境特征可能对它们造成的影响，我们根据PRISMA指南进行了系统的综述。使用关键字组合，我们确定了66个研究的集合，包括327个采样点，通过16S rDNA基因高通量测序报告了干旱土壤细菌群落组成。为了确定可以调节细菌群落的因素，我们提取了地理，环境和物理化学数据。结果表明，即使每个采样点都被归类为干旱地区，它们在干旱环境中以及干旱环境之间和海拔之间，高度，年平均温度（MAT），土壤pH值和电导率的变化都很大。我们显示，与非干旱土壤微生物群落相比，干旱土壤表现出较高的放线菌数量和较低的变形杆菌，蓝细菌和扁平菌数量，这表明在干旱土壤中微生物结构似乎受到MAP和MAT的强烈调节，而不受pH的影响。我们观察到在研究中几乎没有描述环境和物理化学特征，因此，我们提出了一份报告指南以进行进一步分析，这将有助于加深人们对干旱土壤中微生物组与非生物因子之间关系的认识。最后，为了了解学术合作的前景，我们对作者的网络进行了分析，从而证实了本研究主题中的连通性和合作程度较低。考虑到了解微生物在干旱土壤中如何发展和变化至关重要，我们的分析强调需要加强全球研究小组之间的合作。在本研究主题中证实了较低的连通性和协作性。考虑到了解微生物在干旱土壤中如何发展和变化至关重要，我们的分析强调需要加强全球研究小组之间的合作。在本研究主题中证实了较低的连通性和协作性。考虑到了解微生物在干旱土壤中如何发展和变化至关重要，我们的分析强调需要加强全球研究小组之间的合作。