State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, P.R. China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100039, P.R. China.
FEMS Microbiol Ecol. 2023 Jun 16;99(7). doi: 10.1093/femsec/fiad066.
Glaciers in high-altitude mountain regions are retreating rapidly due to global warming, exposing deglaciated soils to extreme environmental conditions, and microbial colonization. However, knowledge about chemolithoautotrophic microbes, which play important roles in the development of oligotrophic deglaciated soils prior to plant colonization, remains elusive in deglaciated soils. Using real-time quantitative PCR and clone library methods, the diversity and succession of the chemolithoautotrophic microbial community harboring the cbbM gene across a 14-year deglaciation chronosequence on the Tibetan Plateau were determined. The abundance of the cbbM gene remained stable for the first 8 years after deglaciation and then increased significantly, ranging from 105 to 107 gene copies g-1 soil (P < 0.001). Soil total carbon increased gradually to 5-year deglaciation and then decreased. While total nitrogen and total sulfur levels were low throughout the chronosequence. Chemolithoautotrophs were related to Gammaproteobacteria and Betaproteobacteria, with the former dominating early deglaciated soils and the latter dominating older deglaciated soils. The diversity of chemolithoautotrophs was high in mid-age deglaciated soils (6-year-old) and was low in early (3-year-old) and older deglaciated soils (12-year-old). Our findings revealed that chemolithoautotrophic microbes colonize deglaciated soils quickly and follow a clear successional pattern across recently deglaciated chronosequences.
由于全球变暖，高海拔山区的冰川迅速消退，使冰川退缩土壤暴露在极端环境条件和微生物定殖下。然而，在植物定殖之前，对于在贫营养冰川退缩土壤中发挥重要作用的化能自养微生物，在冰川退缩土壤中仍然知之甚少。本研究采用实时定量 PCR 和克隆文库方法，研究了青藏高原冰川退缩 14 年时间序列上 cbbM 基因驱动的化能自养微生物群落的多样性和演替。冰川退缩后 8 年内，cbbM 基因丰度保持稳定，然后显著增加，范围为 105 到 107 个基因拷贝 g-1 土壤（P < 0.001）。土壤总碳逐渐增加到 5 年冰川退缩，然后减少。而总氮和总硫水平在整个时间序列中都较低。化能自养菌与γ变形菌纲和β变形菌纲有关，前者在早期冰川退缩土壤中占主导地位，后者在较老的冰川退缩土壤中占主导地位。化能自养菌的多样性在中龄冰川退缩土壤（6 年）中较高，在早期（3 年）和较老的冰川退缩土壤（12 年）中较低。本研究结果表明，化能自养微生物快速定殖冰川退缩土壤，并在最近的冰川退缩时间序列上呈现明显的演替模式。
