Elevational patterns in the diversity and composition of soil archaeal and bacterial communities depend on climate, vegetation, and soil properties in an arid mountain ecosystem

• Soil archaea exhibited a hump-shaped elevation pattern in α-diversity. • Soil bacterial α-diversity showed a monotonic increasing pattern like plants. • MAP outcompeted MAT exerted a significant influence on microbial community structure. • Soil pH, and moisture were the main drivers of archaeal community composition. • Plant community attitudes and available nitrogen greatly shaped bacterial community structure. The continuous changes in climate, vegetation, and soil properties along elevational gradients provide a space-for-time method for probing the mechanisms behind the generation and maintenance of biodiversity. However, elevational patterns of soil microbial communities along elevational gradients and their driving mechanisms in arid mountain are poorly understood. The metagenomics technique was employed to examine the α-diversity and community composition of soil archaea and bacteria along elevational gradients ranging from 1707 to 3548 m in Mt. Middle Kunlun, China. The number of bacterial sequences was significantly higher than that of archaeal sequences, and the dominant phyla and genera in both communities showed significant differences in abundance across elevations. The α-diversity (Shannon index) displayed a monotonically increasing pattern for bacteria and a hump-shaped pattern for archaea, while the community composition of both archaea and bacteria demonstrated a similar hump-shaped trend. The community composition of archaea and bacteria were influenced by elevation via precipitation, vegetation, and soil properties. However, the underlying factors for these two microbial communities were different. Environmental-physiological constraints (e.g., soil water content and pH) were determined to be the main drivers of archaeal community composition. Bacterial community composition was primarily influenced by vegetation factors (such as plant diversity and cover) and soil nutrients (such as available nitrogen). This research offers a thorough examination of the biogeography of soil microbes in precipitation-sensitive or arid mountain ecosystems.