不同生境下黄河三角洲湿地土壤菌群结构与功能特征

Structural and functional characteristics of soil microbial communities in different habitats of the Yellow River Delta wetland

摘要:

目的 探究黄河三角洲湿地生态系统中3种不同生境的微生物群落组成、功能特征及垂直分布特点，为湿地生态的靶向修复和可持续管理提供理论支持与潜在微生物资源。方法 采用16S rRNA基因扩增子测序和代谢组学分析研究植被覆盖区、裸地和生物栖息区3种生境土壤细菌群落的组成和结构差异，分析不同土壤深度细菌群落特征，以及生境特异性细菌-代谢物间潜在的互作关系。结果 3种生境中共有优势菌门为变形菌门(Proteobacteria)和拟杆菌门(Bacteroidota)。浅层土壤特有优势菌门为出芽单胞菌门(Gemmatimonadota)，深层土壤特有优势菌门为厚壁菌门(Firmicutes)。在不同土壤深度上，植被覆盖区的unidentified MBNT15、裸地的盐单胞菌属(Halomonas)，以及生物栖息区中未鉴定红细菌科(unidentified Rhodobacteraceae)和伍斯氏菌属(Woeseia)存在显著差异，且芽孢杆菌属(Bacillus)在各生境深层土壤中普遍富集。代谢物分析显示，植被覆盖区中鞘氨醇、3-吲哚丙烯酸、2,4-二羟基苯甲酸和全氟辛酸含量较高；裸地中脱氧胆酸含量最高，生物栖息区中磺胺甲噁唑含量最高，且l-色氨酸含量较低。相关性分析表明，植被覆盖区中，藤黄微球菌(Micrococcus luteus)和膝形假单胞菌(Pseudomonas geniculata)与鞘氨醇和全氟辛酸呈显著正相关；卤水糖小螺菌(Saccharospirillum salsuginis)与3-吲哚丙烯酸和2,4-二羟基苯甲酸呈显著正相关。裸地中掘越氏芽孢杆菌(Bacillus horikoshii)与脱氧胆酸呈显著正相关。生物栖息区中樊氏盐单胞菌(Halomonas ventosae)与l-色氨酸呈显著正相关；库尔勒盐单胞菌(Halomonas korlensis)与磺胺甲噁唑呈显著正相关。结论 不同土壤深度对微生物群落结构有显著影响，且土壤菌群结构与功能特征具有生境特异性。植被覆盖区中富集的M. luteus等菌可能通过调节代谢物促进植物生长和增强抗逆性；裸地中富集的Bacillus具有分解鸟类粪便的功能；生物栖息区中显著差异菌种H. ventosae等具有通过调节代谢物维持螃蟹栖息生态健康的潜力。这些发现为湿地生态系统的微生物调控和管理提供了新的视角。

关键词:黄河三角洲湿地;不同生境;土壤深度;微生物群落结构;差异代谢物;关联性

Abstract:

Objective To study the composition, functional characteristics, and vertical distribution features of microbial communities of three different habitats in the Yellow River Delta wetland ecosystem, and provide theoretical support and potential microbial resources for targeted restoration and sustainable management of wetland ecology.Methods By using 16S rRNA gene amplicon sequencing and metabolomics analyses, we compared the composition and structures of soil bacterial communities in three habitats (vegetation-covered area, bare land, and biohabitat), and analyzed the characteristics of bacterial communities at varying soil depths as well as the potential interactions between habitat-specific bacteria and metabolites.Results The dominant phyla in the three habitats were Proteobacteria and Bacteroidota. The dominant phyla specific to the shallow and deep soil layers were Gemmatimonadota and Firmicutes, respectively. The unidentified MBNT15 in the vegetation-covered area, Halomonas in the bare land, and unidentified Rhodobacteraceae and Woeseia in the biohabitat showed significantly different abundance between different depths, and Bacillus was enriched in the deeper soil layer of all the three habitats. Metabolomic analysis revealed that the vegetation-covered area showed higher levels of sphinganine, 3-indoleacrylic acid, 2,4-dihydroxybenzoic acid, and perfluorooctanoic acid. Deoxycholic acid had the highest level in the bare land, while sulfamethoxazole was the highest in the biohabitat, which had lower level of l-tryptophan. Correlation analysis revealed that in the vegetation-covered area, Micrococcus luteus and Pseudomonas geniculata showed significantly positive correlations with sphinganine and perfluorooctanoic acid. Saccharospirillum salsuginis had significantly positive correlations with 3-indoleacrylic acid and 2,4-dihydroxybenzoic acid. In the bare land, Bacillus horikoshii showed a significantly positive correlation with deoxycholic acid. In the biohabitat, Halomonas ventosae had a significantly positive correlation with l-tryptophan, while Halomonas korlensis showed a significantly positive correlation with sulfamethoxazole.Conclusion Our study demonstrated that varying soil depths significantly impact the structure of microbial communities, and the structural and functional characteristics of soil microbial communities exhibit habitat specificity. The enriched bacteria such as M. luteus in the vegetation-covered area may promote plant growth and enhance stress resistance by regulating metabolites. The enriched Bacillus in the bare land plays a role in decomposing bird feces. The unique bacteria such as H. ventosae in the biohabitat demonstrate the potential for maintaining the ecological health of crab habitats through metabolite regulation. These findings offer new insights into the microbial regulation and management of wetland ecosystems.

Key words:Yellow River Delta wetland;different habitats;soil depth;microbial community structure;differential metabolites;correlation