Structural Variations of Bacterial Community Driven by Sphagnum Microhabitat Differentiation in a Subalpine Peatland

Abstract

Sphagnum microbiomes play an important role in the northern peatland ecosystems. However, information about above and belowground microbiomes related to Sphagnum at subtropical area remains largely limited. In this study, microbial communities from Sphagnum palustre peat, S. palustre green part, and S. palustre brown part at the Dajiuhu Peatland, in central China were investigated via 16S rRNA gene amplicon sequencing. Results indicated that Alphaproteobacteria was the dominant class in all samples, and the classes Acidobacteria and Gammaproteobacteria were abundant in S. palustre peat and S. palustre brown part samples, respectively. In contrast, the class Cyanobacteria dominated in S. palustre green part samples. Microhabitat differentiation mainly contributes to structural differences of bacterial microbiome. In the S. palustre peat, microbial communities were significantly shaped by water table and total nitrogen content. Our study is a systematical investigation on above and belowground bacterial microbiome in a subalpine Sphagnum peatland and the results offer new knowledge about the distribution of bacterial microbiome associated with different microhabitats in subtropical area.

Differential Impacts of Water Table and Temperature on Bacterial Communities in Pore Water From a Subalpine Peatland, Central China

“…Generally, the wet season is from April to September, and dry season is from October to March. The vegetation mainly consists of Carex spp., Sphagnum palustre, Sanguisorba officinalis, and Euphorbia esula accompanying shrubs (Tian et al, 2019). Sphagnum mosses are known as the major charcoal-forming plants in acidic peatlands and greatly contribute to peatland development (Tian et al, 2020).…”

“…For example, DO and ORP (Table 1) were negatively related to the WT (Supplementary Figure 4). WT fluctuation can change the depth of the oxic-anoxic interface (Tian et al, 2019), resulting in the subsequent shifts in electron donors and acceptors (Brune et al, 2000;Daffonchio et al, 2006). High WT facilitates anaerobic processes, and low WT accelerates the biodegradation of organic matters due to the penetration of oxygen and expansion of the oxic zone.…”

“…Microbial communities in peatland ecosystems are key players in nutrient cycles, carbon sequestration, and greenhouse gas emissions (Kip et al, 2010;Dedysh, 2011;Yang et al, 2017). Microbial communities in peatlands are sensitive to water table (WT) fluctuations (Jaatinen et al, 2007;Urbanová and Bárta, 2016;Tian et al, 2019) and temperature changes (Fenner et al, 2007;Kolton et al, 2019), which are two major factors of concern in the context of climate change. Understanding the variations of microbial community structures and carbon utilization with WT fluctuations and temperature changes will help us comprehend the dynamics of carbon cycle in peatland ecosystems under climate change scenarios.…”

Rare Species Shift the Structure of Bacterial Communities Across Sphagnum Compartments in a Subalpine Peatland

“…Sphagnum mosses are the prevalent vegetation in acidic peatlands and greatly contribute to peatland development. Sphagnum mosses host diverse bacterial communities either endosymbiotic or ectosymbiotic with the plant (Opelt et al, 2007a,b;Bragina et al, 2012Bragina et al, , 2014Tian et al, 2019). The bacterial communities can produce antifungal compounds to improve pathogen defense of hosts and provide nitrogen for Sphagnum mosses via nitrogen-fixing bacteria such as Burkholderia (Opelt et al, 2007c;Shcherbakov et al, 2013Shcherbakov et al, , 2015.…”

“…Generally, microbial communities in peatlands are comprised of a few dominant taxa (relative abundance >1%) with a long tail of low abundance species (Gilbert and Mitchell, 2006;Andersen et al, 2013;Tian et al, 2019), as well as in other habitats (Delgado-Baquerizo et al, 2018). These abundant taxa largely contribute to carbon cycling and energy flow due to their broad niche, high competitive ability and fast growth rate (Campbell et al, 2011).…”