Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Key Laboratory of Grassland Ecology and Restoration, Ministry of Agriculture, Hohhot, 010010, China.
Institute for Applied and Environmental Microbiology, College of Life Science, Inner Mongolia Agricultural University, Hohhot, 010018, China.
Environ Microbiol. 2021 Jul;23(7):3554-3567. doi: 10.1111/1462-2920.15459. Epub 2021 Jun 28.
Several significant ecosystem services are performed by biological soil crusts (BSCs) in drylands, wherein photoautotrophic microorganisms are commonly critical contributors. However, aerobic anoxygenic phototrophic bacteria (AAnPB) are rarely reported in BSCs, despite being the second major branch of Earth's phototrophic microbes. Here, we collected different types of BSCs and their subsoils from temperate deserts, investigated distributions of AAnPB communities among BSCs using cultivation and high-throughput sequencing approaches, predicted keystone species by co-occurrence network analysis, and verified their effects on BSCs formation through microcosm experiments. The absolute abundances and diversity of AAnPB were higher in BSCs and were closely related with BSCs successional stages, as well as soil organic carbon contents. AAnPB communities in both BSCs and their subsoils were dominated by Proteobacteria and Alphaproteobacteria, specifically Acetobacteraceae, Rhodospirillaceae, Roseiflexaceae, Sphingomonadaceae and Caulobacteraceae families. Mean annual precipitation, pH and available nutrients were the primary factors that shaped AAnPB community structures. The predicted keystone species belonged to the families Acetobacteraceae, Rhodospirillaceae and Sphingomonadanceae. Microcosm experiments demonstrated that inoculation with strains from the three families greatly accelerated the formation and development of BSCs. These observations suggest that AAnPB are likely important functional groups in BSCs that significantly contribute to their formation and important ecosystem services.
生物土壤结皮（BSCs）在干旱地区发挥着多种重要的生态系统服务功能，其中光自养微生物通常是至关重要的贡献者。然而，尽管好氧厌氧光合细菌（AAnPB）是地球光养微生物的第二大分支，但在 BSCs 中却很少有报道。在这里，我们从温带沙漠中收集了不同类型的 BSCs 及其亚土壤，使用培养和高通量测序方法研究了 AAnPB 群落在 BSCs 中的分布，通过共生网络分析预测关键种，并通过微宇宙实验验证它们对 BSCs 形成的影响。AAnPB 的绝对丰度和多样性在 BSCs 中较高，与 BSCs 的演替阶段以及土壤有机碳含量密切相关。BSCs 和亚土壤中的 AAnPB 群落均以变形菌门和α变形菌门为主，特别是醋杆菌科、红螺旋菌科、玫瑰杆菌科、鞘脂单胞菌科和柄杆菌科。年平均降水量、pH 值和可用养分是塑造 AAnPB 群落结构的主要因素。预测的关键种属于醋杆菌科、红螺旋菌科和鞘脂单胞菌科。微宇宙实验表明，接种来自这三个科的菌株可大大加速 BSCs 的形成和发展。这些观察结果表明，AAnPB 可能是 BSCs 中的重要功能群，对其形成和重要的生态系统服务有重要贡献。
