Almost one third of Earth’s land surface is arid, with deserts alone covering more than 46 million square kilometres. Nearly 2.1 billion people inhabit deserts or drylands and these regions are also home to a great diversity of plant and animal species including many that are unique to them. Aridity is a multifaceted environmental stress combining a lack of water with limited food availability and typically extremes of temperature, impacting animal species across the planet from polar cold valleys, to Andean deserts and the Sahara. These harsh environments are also home to diverse microbial communities, demonstrating the ability of bacteria, fungi and archaea to settle and live in some of the toughest locations known. We now understand that these microbial ecosystems i.e. microbiotas, the sum total of microbial life across and within an environment, interact across both the environment, and the macroscopic organisms residing in these arid environments. Although multiple studies have explored these microbial communities in different arid environments, few studies have examined the microbiota of animals which are themselves arid-adapted. Here we aim to review the interactions between arid environments and the microbial communities which inhabit them, covering hot and cold deserts, the challenges these environments pose and some issues arising from limitations in the field. We also consider the work carried out on arid-adapted animal microbiotas, to investigate if any shared patterns or trends exist, whether between organisms or between the animals and the wider arid environment microbial communities. We determine if there are any patterns across studies potentially demonstrating a general impact of aridity on animal-associated microbiomes or benefits from aridity-adapted microbiomes for animals. In the context of increasing desertification and climate change it is important to understand the connections between the three pillars of microbiome, host genome and environment.

中文翻译：

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一个相当枯燥的话题；干旱相关微生物群落研究调查

地球陆地表面几乎有三分之一是干旱的，仅沙漠就面积超过 4600 万平方公里。近 21 亿人居住在沙漠或旱地，这些地区也是多种多样的植物和动物物种的家园，其中包括许多当地特有的植物和动物物种。干旱是一种多方面的环境压力，结合了缺水、有限的食物供应和典型的极端温度，影响着从极地寒冷山谷到安第斯沙漠和撒哈拉沙漠的全球动物物种。这些恶劣的环境也是多种微生物群落的家园，证明了细菌、真菌和古细菌在一些已知最恶劣的地方定居和生活的能力。我们现在了解到，这些微生物生态系统，即微生物群，是环境中和环境中微生物生命的总和，与环境以及居住在这些干旱环境中的宏观生物体相互作用。尽管多项研究探索了不同干旱环境中的这些微生物群落，但很少有研究检查本身适应干旱的动物的微生物群。在这里，我们的目的是回顾干旱环境与栖息在其中的微生物群落之间的相互作用，包括炎热和寒冷的沙漠、这些环境带来的挑战以及由于该领域的局限性而产生的一些问题。我们还考虑对适应干旱的动物微生物群进行的工作，以调查是否存在任何共同的模式或趋势，无论是在生物体之间还是在动物与更广泛的干旱环境微生物群落之间。我们确定研究中是否存在任何模式可能证明干旱对动物相关微生物组的总体影响或动物适应干旱的微生物组的益处。在荒漠化和气候变化加剧的背景下，了解微生物组、宿主基因组和环境三大支柱之间的联系非常重要。