黄河三角洲原生演替中土壤微生物群落结构分析

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

摘要:

[目的] 黄河三角洲区域具有重要的湿地生态系统。碱蓬、野大豆和芦苇是该地区典型的盐生植物。本研究针对碱蓬、野大豆和芦苇混生植物的根际土壤微生物群落组成和功能基因进行了分析比较。[方法] 对碱蓬，野大豆-芦苇混生植物的根际微生物菌群和光滩土壤菌群进行了宏基因组测序，使用COG和KEGG数据库对微生物菌群的功能进行了注释和比较。[结果] 本研究结果表明，变形菌门是3个取样点的主要菌门，其在碱蓬、野大豆-芦苇根际土壤中的相对含量比光滩土壤分别多28.8%和10.6%。此外，拟杆菌门、放线菌门和芽单胞菌门是3个取样点中的优势物种。中华根瘤菌属是野大豆-芦苇混生植物根际土壤的最主要的属。对功能基因进行分析表明，光滩土壤中的功能基因的数量多于碱蓬根际土壤和野大豆-芦苇混生植物根际土壤的功能基因数。在这3个位点中，氨基酸代谢、碳水化合物代谢和能量代谢，以及无机离子转运和代谢的基因最多。[结论] 本研究为发掘有价值的微生物资源和海岸带盐碱土壤修复提供了一定的理论基础。

关键词:宏基因组测序;微生物多样性;盐生植物;生态演替;黄河三角洲

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.

Key words:metagenomic sequencing;microbial diversity;halophyte;ecological succession;Yellow River Delta