Investigation of the Ecological Roles of Putative Keystone Taxa during Tailing Revegetation

Abstract

Metal contamination released from tailings is a global environmental concern. Although phytoremediation is a promising remediation method, its practice is often impeded by the adverse tailing geochemical conditions, which suppress biological activities. The ecosystem services provided by indigenous microorganisms could alter environmental conditions and facilitate revegetation in tailings. During the process, the keystone taxa of the microbial community are assumed an essential role in regulating the community composition and functions. The identity and the environmental functions of the keystone taxa during tailing revegetation, however, remain unelucidated. The current study compared the microbial community composition and interactions of two contrasting stibnite (Sb 2 S 3 ) tailings, one revegetated and one unvegetated. The microbial interaction networks and keystone taxa were significantly different in the two tailings. Similar keystone taxa were also identified in other revegetated tailings, but not in their corresponding unvegetated tailings. Metagenome-assembled genomes (MAGs) indicated that the keystone taxa in the revegetated tailing may use both organic and inorganic energy sources (e.g., sulfur, arsenic, and antimony). They could also facilitate plant growth since a number of plant-growth-promoting genes, including phosphorus solubilization and siderophore production genes, were encoded. The current study suggests that keystone taxa may play important roles in tailing revegetation by providing nutrients, such as P and Fe, and promoting plant growth.

Importance of microbial communities at the root-soil interface for extracellular polymeric substances and soil aggregation in semiarid grasslands

“…Sequences with closest identification as Pseudomonadaceae and Burkholderiaceae (Gammaproteobacteria) were also more abundant in the Anthyllis rhizoplane (Table 1). Sequences from these families have recently been identified as keystone taxa in a revegetation project of mine tailings (Sun et al, 2020). Strains of both families are known to play a role in promoting plant growth (Lucy et al, 2004), whereas members of the Burkholderiaceae were also strongly associated with CO 2 fixation mechanisms (Sun et al, 2020).…”

“…Sequences from these families have recently been identified as keystone taxa in a revegetation project of mine tailings (Sun et al, 2020). Strains of both families are known to play a role in promoting plant growth (Lucy et al, 2004), whereas members of the Burkholderiaceae were also strongly associated with CO 2 fixation mechanisms (Sun et al, 2020). From the Pseudomonadaceae several isolates have been found to promote the growth of another Anthyllis plant species in mine soils, by solubilizing phosphorus and producing auxins and siderophores (Soussou et al, 2017).…”

Metabolic potentials of members of the class Acidobacteriia in metal‐contaminated soils revealed by metagenomic analysis

“…S3) (Banerjee et al, 2016;Banerjee et al, 2018). Secondary metabolite biosynthesis was reported to play a critical function for keystone taxa to affect community composition (Banerjee et al, 2016;Sun et al, 2020c). The capability of secondary metabolite biosynthesis by Acidobacteriia may facilitate their ecological functions in the microbial community.…”

Bacterial Communities of Sediments in a Seawater-Freshwater Transition Zone During the Wet and Dry Seasons in Pearl River Estuary

“…However, in January samples in ZH, the proportion of positive link was much higher than that of negative link as a result of the reduced proportion of negative links. The keystone taxa were identi ed according to the standard of the nodes with low betweenness centralities and high degrees [38,39]. In January samples in ZH, a total of sixteen ASVs were de ned as keystone taxa (Table S1), which were further assigned to Moraxellaceae (eight ASVs) and Planococcaceae (eight ASVs) at family level.…”

“…These keystone taxa signi cantly in uence material transformation, energy metabolism, and/or nutrient cycling in response to geochemical and biological factors because they can choose different environmentdependent survival strategies to develop the whole microbial communities in their favor [53][54][55], and the absence of these keystone taxa can potentially cause tremendous shifts in the composition and function of the microbial communities [56,57]. Usually, the keystone taxa were identi ed according to the criteria of high degree nodes and low betweenness [38,39]. In current study, Moraxellaceae and Planococcaceae were identi ed as the keystone bacteria based on multiple pieces of evidence, and they had positive correlations with EC (Figs.…”