Soil Organic Carbon Chemical Functional Groups under Different Revegetation Types Are Coupled with Changes in the Microbial Community Composition and the Functional Genes

Abstract

Different revegetatiom types can affect the chemical composition of soil organic carbon (SOC), soil microbial community and the functional genes related to carbon cycle. However, the relationships between SOC chemical functional groups and soil microbial communities and the functional genes remains poorly unclear under different revegetation types. Using the solid-state 13C nuclear magnetic resonance (NMR) spectroscopy, we examined changes in the SOC chemical composition of five soils (0–10 cm depth) from Larix gmelinii Rupr. (LG), Pinus koraiensis Sieb. (PK), Quercus mongolica Fisch. (QM), Juglans mandshurica Maxim. (JM), and conifer-broadleaf forest (CB). And the soil microbial community genes related to metabolism of macro-molecular compounds were determined via whole genome shotgun based on Illumina HiSeq. Our results indicated that broadleaf forests (JM, QM) had increased the contents of soil total carbon (C), total nitrogen (N), dissolved organic carbon (DOC), and microbial biomass carbon (MBC), compared with coniferous forests (LG, PK) and the conifer-broadleaf forest (CB). While, the coniferous forests generated a lower O-alcoxyl C, a higher alkyl C, and the ratio of alkyl C/O-alkyl C than broadleaf forests. A total of four kingdoms were identified via whole metagenome shotgun sequencing, including eight archaea, 55 bacteria, 15 eukaryota, and two viruses, giving a total 80 phyla. The contents of alkyne C, phenolic C, methoxyl C, COO/NC=O, and alkyl C were strong related to the composition of soil microbial community and their contents illuminated a major part of the variation in soil microbial composition. We detected seven corresponding macro-molecular compounds of different organic carbon functional group, and 244 genes related to metabolism across all samples, and soil total C, total N, and DOC could be the main factors for microbial functional gene composition. Interestingly, the relative abundances of different SOC chemical functional groups, the phylogenetic distance for microbes, the genes of C cycling based on the KEGG database, and the relative abundance of genes related to metabolism of macro-molecular compounds of different SOC chemical functional groups under different revegetation types all could be divided into three groups, including PK plus LG, JM plus QM, and CB. Our results also illustrated that variations in SOC chemical functional groups were strongly associated with changes of soil microbial community taxa and functional genes, which might be affected by the changes of soil characteristics.

Soil pH and Organic Carbon Properties Drive Soil Bacterial Communities in Surface and Deep Layers Along an Elevational Gradient

“…In addition, the abundances of oligotrophic Gemmatimonadetes and Chloroflexi were positively correlated with soil C availability for surface soils, which was contrary to what their life strategies would predict. Previous studies have also suggested that Gemmatimonadetes and Chloroflexi can degrade recalcitrant compounds (Wilms et al, 2006;Pascault et al, 2013;Chen et al, 2015;Deng et al, 2019). In this study, Gemmatimonadetes (Gemm-1 at the class level) and Chloroflexi (TK10 at the class level) were positively correlated with RP% (i.e., aromatic C fraction), which suggests that resource preferences can partly explain the variations in the abundances of Gemmatimonadetes and Chloroflexi.…”

“…Thus, SOC content and mineralization rate, which represent soil C availability, are important determinants of soil bacterial diversity and composition (Ding et al, 2015;Yao et al, 2017;Tian et al, 2018). Besides, the chemical components of SOC (known as soil labile or recalcitrant C fractions) are also demonstrated to affect soil bacterial communities (Davinic et al, 2012;Ng et al, 2014;Li et al, 2018;Deng et al, 2019), since individual bacterial taxa exhibit different resource preferences (Paterson et al, 2008;Di Lonardo et al, 2017;Ivanova et al, 2018). For example, Acidobacteria, Delta-proteobacteria, and Gemmatimonadetes can degrade more recalcitrant substrates, while Actinobacteria and Beta-proteobacteria can utilize fresh and labile substrate (Pascault et al, 2013;Chen et al, 2015).…”

Impact of short-rotation willow as riparian land-use practice on soil organic carbon fractions and composition from two contiguous wetland systems in the prairie pothole region

“…Research has suggested that altered leaf litter quality due to the difference in vegetation can control the chemical composition and structure of SOC (Guo et al 2016). The RC:LC ratio can better explain the degree of decomposition and the stability of SOC via its enrichment in phenolic, aromatic, and carboxylic groups relative to polysaccharides (Deng et al 2019). Contrasting land-use practices signi cantly affected the RC:LC ratio of phenolic to polysaccharide (alkyl-C/O-alkyl-C) and amide to polysaccharide (amide/O-alkyl-C) in both sites in our study.…”

“…The quality, function, and biochemical stability of SOC depend on the relative abundance of soil LC versus RC functional groups (Beer et al 2008). As the soil organic matter (SOM) under different vegetation types from contrasting land-use practices decomposes, the chemical composition of SOC changes (La eur et al 2015;Deng et al 2019). Advanced analytical techniques such as Fourier Transform Infrared (FTIR) spectroscopy can reveal the biochemical characteristics at molecular-scale and relative abundance of C compounds (i.e., polysaccharides, phenolic, amides, aromatic, carboxylic) via the ratios of RC and LC fractions (Calderón et al 2013).…”

Soil Organic Carbon Distribution and Its Response to Soil Erosion Based on EEM-PARAFAC and Stable Carbon Isotope, a Field Study in the Rocky Desertification Control of South China Karst

“…It can be seen from this study that aromaticity, hydrophobicity, and molecular weight of different soil layers planted with Zanthoxyhum planispinum var. Generally speaking, the shallow soil organic matter mainly comes from the direct input of plant litters, and the overlying vegetation types directly affect the SOC content [43][44][45][46]. DOC is a more active part in SOC, and it is closely related to microorganisms, temperature, humidity, and other factors [47].…”