Potential complementary functions among bacteria, fungi, and archaea involved in carbon cycle during reversal of desertification

Abstract

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.

Microbial function regulates the effect of vegetation restoration on the contribution of biocrusts to soil respiration in drylands

“…This exception may be due to the relatively high abundance of fungal communities in the lichen‐biocrusted soil (Figure S10); most of the functional genes are derived from bacterial rather than fungal communities (Zhao et al, 2020). Moreover, bacterial decomposers favour labile substrates (such as starch, hemicellulose and pectin), whereas fungi prefer complex substrates (such as cellulose, terpenes, chitin and vanillin/lignin; Güsewell & Gessner, 2009; Wang, Wang, et al, 2021), which is consistent with the results obtained for the lichen‐biocrusted soil.…”

“…Previous studies showed that the structure and function of soil microbial communities were different under different types of biocrusts (Wang, Wang, et al, 2021; Zhao et al, 2020). Soil microorganisms can adjust their respiratory function by altering their metabolism and community structure (Brown et al, 2004), and they are the main contributors to soil respiration (Guo et al, 2020; Tian et al, 2022), especially in dryland ecosystems where vascular plants are usually quite sparse (García‐Palacios et al, 2018; Guan et al, 2019).…”

“…Biocrusts are ecosystem engineers at the atmosphere–soil interface, and they regulate a wide range of ecosystem functions, including C budgets (Dacal et al, 2020; García‐Palacios et al, 2018), nitrogen (N) cycles (Koranda & Michelsen, 2021; Maier et al, 2021), phosphorus (P) cycles (Kurth et al, 2021), hydrological processes (Eldridge et al, 2020), soil thermal properties (Xiao, Ma, et al, 2019) and soil stability (Algayer et al, 2014). Specifically, biocrusts regulate soil CO 2 flux not only directly through photosynthesis (Li, Hui, et al, 2021) and respiration (Guan et al, 2021, 2022) but also indirectly by altering the soil temperature (Xiao, Ma, et al, 2019), moisture (Eldridge et al, 2020), N availability (Koranda & Michelsen, 2021) and microbial community and functional structure (Wang, Wang, et al, 2021). For example, soil respiration at microsites with high biocrust coverage is significantly higher than that at microsites with low biocrust coverage (Escolar et al, 2015; Maestre et al, 2013) or in bare soils (Morillas et al, 2017; Yao et al, 2020), and biocrusts can contribute to more than 40% of CO 2 flux via soil respiration (Castillo‐Monroy et al, 2011).…”

Reshaping of soil carbon and nitrogen contents in quincentenary ancient rice terraces: The role of both short-term abandonment and prokaryotic functional groups

“…While transformation genes of bacterial carbon and nitrogen were significantly associated with SOC and TN contents, transformation genes of only archaeal nitrogen were significantly associated with TN content. Wang et al ( 2021 ) reported that soil bacterial genes contributed 84.53 and 95.62% to carbon decomposition and fixation, respectively, while archaeal genes contributed only 1.09 and 4.05%, respectively, through the detection of functional genes in soils of desert ecosystem. It may be that archaea are more biased toward soil nitrogen transformation, while bacteria specialize in carbon and nitrogen transformations (Monteux et al, 2020 ; Wang et al, 2021 ).…”

“…Wang et al ( 2021 ) reported that soil bacterial genes contributed 84.53 and 95.62% to carbon decomposition and fixation, respectively, while archaeal genes contributed only 1.09 and 4.05%, respectively, through the detection of functional genes in soils of desert ecosystem. It may be that archaea are more biased toward soil nitrogen transformation, while bacteria specialize in carbon and nitrogen transformations (Monteux et al, 2020 ; Wang et al, 2021 ). Collectively, the abandonment of ancient rice terraces changed soil properties, such as pH and -N, which in turn altered the bacterial and archaeal community structures and reduced the gene abundance of the transformationfunctional groups of carbon and nitrogen.…”