Development of biological soil crusts (BSCs) on bare land is a sign of reversal of desertification, and microbial communities of BSCs are the biogeochemical engineers of desert ecosystems. However, regulation of different microbial groups involved in the carbon (C) cycle is not clear. This study investigated the correlation between bacteria, fungi, and archaea of BSCs involved in the C cycle during reversal of desertification through community abundance analysis by quantitative PCR and functional gene detection using GeoChip 5.0. Among the known C cycle genes found in BSCs, 84.5% of C degradation genes, 95% of C fixation genes, and all of methane oxidation genes were derived from bacteria owing to their highest proportion among the total microbial abundance of BSCs; some recalcitrant C degradation genes were derived from fungi; and other C fixation pathway and methanogenesis genes originated from archaea. The increased abundance of bacteria and fungi and decreased abundance of archaea during reversal of desertification, as well as the difference in C cycle genes of the three microbial groups, indicated the functional complementarity among these microorganisms involved in C cycle. At the early stage of BSC development, archaea, and bacteria provide available C sources by autotrophic CO₂ fixation pathway; bacteria play important roles in C degradation, C fixation, and methane oxidation during the entire BSC development process; and fungi mainly degrade lignin at the later stage of BSC development. Thus, cooperation among BSC microflora altered C cycle during reversal of desertification.

中文翻译：

---

荒漠化逆转过程中参与碳循环的细菌，真菌和古细菌之间的潜在互补功能

在裸露的土地上发展生物土壤结皮（BSC）是荒漠化逆转的标志，而BSC的微生物群落是沙漠生态系统的生物地球化学工程师。但是，不清楚参与碳（C）循环的不同微生物群的调控。这项研究通过定量PCR的社区丰度分析和使用GeoChip 5.0进行功能基因检测，研究了荒漠化逆转过程中参与C循环的BSC的细菌，真菌和古细菌之间的相关性。在BSC中发现的已知C循环基因中，有84.5％的C降解基因，95％的C固定基因和所有甲烷氧化基因均来自细菌，这是由于它们在BSC的微生物总数中所占比例最高。一些顽固的C降解基因来自真菌。以及其他C固定途径和产甲烷基因起源于古细菌。荒漠化逆转过程中细菌和真菌的丰度增加和古细菌的丰度降低，以及三个微生物群的C循环基因差异，表明这些参与C循环的微生物之间的功能互补。在BSC发展的早期，古细菌和细菌通过自养CO提供可用的C源₂固定途径；在整个BSC发育过程中，细菌在C降解，C固定和甲烷氧化中起重要作用；BSC发展的后期，真菌主要降解木质素。因此，在沙漠化逆转过程中，BSC菌群之间的合作改变了C循环。