Ji Mukan, Kong Weidong, Stegen James, Yue Linyan, Wang Fei, Dong Xiaobin, Cowan Don A, Ferrari Belinda C
Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing, 100101, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100039, China.
Environ Microbiol. 2020 Jun;22(6):2261-2272. doi: 10.1111/1462-2920.14993. Epub 2020 Apr 2.
Rare biosphere represents the majority of Earth's biodiversity and performs vital ecological functions, yet little is known about its biogeographical patterns and community assembly processes in terrestrial ecosystems. Herein, we investigated the community composition and phylogeny of rare (relative abundance <0.1%) and abundant (>1%) bacteria in dryland grassland soils on the Tibetan Plateau. Results revealed similar biogeographical patterns of rare and abundant bacteria at both compositional and phylogenetic levels, but rare subcommunity was more heavily influenced by stochasticity (72%) than the abundant (57%). The compositional variation of rare bacteria was less explained by environmental factors (41%) than that of the abundant (80%), while the phylogeny of rare bacteria (36%) was more explained than that of the abundant (29%). The phylogeny of rare bacteria was equally explained by local factors (soil and vegetation) and geospatial distance (11.5% and 11.9% respectively), while that of the abundant was more explained by geospatial distance (22.1%) than local factors (11.3%). Furthermore, a substantially tighter connection between the community phylogeny and composition was observed in rare (R = 0.65) than in abundant bacteria (R = 0.08). Our study provides novel insights into the assembly processes and biographical patterns of rare and abundant bacteria in dryland soils.
稀有生物圈代表了地球上大部分的生物多样性并发挥着至关重要的生态功能，然而对于其在陆地生态系统中的生物地理格局和群落组装过程却知之甚少。在此，我们调查了青藏高原旱地草地土壤中稀有（相对丰度<0.1%）和常见（>1%）细菌的群落组成和系统发育。结果显示，稀有和常见细菌在组成和系统发育水平上均呈现出相似的生物地理格局，但稀有亚群落比常见亚群落受随机性影响更大（分别为72%和57%）。稀有细菌组成的变化受环境因素解释的比例（41%）低于常见细菌（80%），而稀有细菌系统发育受环境因素解释的比例（36%）高于常见细菌（29%）。稀有细菌的系统发育受局部因素（土壤和植被）和地理空间距离解释的程度相当（分别为11.5%和11.9%），而常见细菌的系统发育受地理空间距离解释的比例（22.1%）高于局部因素（11.3%）。此外，相较于常见细菌（R = 0.08），稀有细菌群落系统发育与组成之间的联系更为紧密（R = 0.65）。我们的研究为旱地土壤中稀有和常见细菌的组装过程及生物地理格局提供了新的见解。
