Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
Microb Ecol. 2022 Jan;83(1):100-113. doi: 10.1007/s00248-021-01734-7. Epub 2021 Mar 17.
Photosynthetic microorganisms are widely distributed in the soil and play an important role in plant-free soil crusts. However, the distribution and environmental drivers of phototrophic microbial communities in physical soil crusts, where the abundance of cyanobacteria is low, are scarcely understood. Here, we performed high-throughput sequencing of pufM and 18S rRNA genes in soil crusts at different elevations on the Tibetan Plateau and used the data combined with environmental variables to analyze the diversity and structure of phototrophic microbial communities. We found that the dominant taxa of aerobic anoxygenic phototrophic bacteria (AAPB) and eukaryotic phototrophic microorganisms (EPM) were shown to shift with elevation. The phototrophic microbial diversity showed a single-peak pattern, with the lowest diversity of AAPB and highest diversity of EPM at middle elevations. Moreover, the elevation and soil property determined the phototrophic microbial community. Soil salts, especially Cl, were the most important for AAPB. Likewise, soil nutrients, especially carbon, were the most important for EPM. The relationship between high-abundance taxa and environmental variables showed that Rhizobiales was significantly negatively correlated with salt ions and positively correlated with chlorophyll. Rhodobacterales showed the strongest and significant positive associations with Cl. Chlorophyceae and Bacillariophyceae were positively correlated with CO. These results indicated that salinity and soil nutrients affected the diversity and structure of microbial communities. This study contributes to our understanding of the diversity, composition, and structure of photosynthetic microorganisms in physical soil crusts and helps in developing new approaches for controlling desertification and salinization and improving the desert ecological environment.
光合微生物广泛分布于土壤中，在无植物土壤结皮中发挥着重要作用。然而，在蓝藻丰度较低的物理土壤结皮中，光养微生物群落的分布和环境驱动因素却鲜为人知。本研究采用高通量测序技术，对青藏高原不同海拔高度的土壤结皮中的 pufM 和 18S rRNA 基因进行了测序，并结合环境变量对光养微生物群落的多样性和结构进行了分析。研究发现，好氧厌氧光合细菌（AAPB）和真核光养微生物（EPM）的优势类群随海拔的升高而发生变化。光养微生物多样性呈单峰模式，中海拔处 AAPB 多样性最低，EPM 多样性最高。此外，海拔和土壤性质决定了光养微生物群落。土壤盐分，特别是 Cl，对 AAPB 影响最大。同样，土壤养分，特别是碳，对 EPM 影响最大。高丰度类群与环境变量之间的关系表明，根瘤菌目与盐离子呈显著负相关，与叶绿素呈显著正相关。红杆菌目与 Cl 呈最强和显著的正相关。绿藻门和硅藻门与 CO 呈正相关。这些结果表明，盐分和土壤养分影响了微生物群落的多样性和结构。本研究有助于我们理解物理土壤结皮中光合微生物的多样性、组成和结构，并为控制荒漠化和盐渍化以及改善沙漠生态环境提供了新的方法。
