Soil microbial community structure along the ecological succession in Yellow River Delta

Abstract:

[Objective] The Yellow River Delta is one of the most important estuary wetland ecosystems in the world. Suaeda glauca (SG), Glycine soja and Phragmites australis (GP) are three typical plants that play important roles in the ecosystem of this region. In this work, we compared the microbial community composition and functional genes of the rhizosphere soils of these typical halophytes with those of bulk soil of the barren wetland (BW) along the saline gradient in the Yellow River Delta. [Methods] Metagenome sequencing was used to analyze the composition and abundance of the microbial communities. COG (Clusters of Orthologous Groups) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses were used to determine the functional gene annotation of the predicted genes. [Results] The results demonstrated that Proteobacteria was the most abundant phylum in all samples. The relative abundance of Proteobacteria in the rhizosphere soils of SG and GP was 28.8% and 10.6% greater than that of the BW, respectively. In addition, Bacteroidetes, Actinobacteria and Gemmatimonadetes were detected as abundant species in the three samples. Sinorhizobium was an abundant species in the GP sample and may be responsible for nitrogen fixation in the rhizosphere soils. Sequence annotation indicated that the number of the predicted functional genes of BW was higher than that of SG and GP. Among them, amino acid metabolism, carbohydrate and energy metabolism, and inorganic ion transport and metabolism genes were abundant in the three samples. [Conclusion] This study demonstrated that different plants and soils have a coordinated effect on the soil microbial communities of the Yellow River Delta, and provided valuable insights on microbial resilience and their potential application on bioremediation of the coastal zone saline-alkali soils.