威海天鹅湖大叶藻(Zostera marina)与日本鳗草(Zostera japonica)根际微生物群落结构及其驱动机制

目的] 本文以威海天鹅湖大叶藻和日本鳗草根际沉积物为主要研究对象，探究不同生长时期的海草根际微生物群落结构多样性，并分析导致微生物群落结构差异的内在因素。方法] 选取威海天鹅湖大叶藻和日本鳗草根际沉积物与非草区表层沉积物，采用高通量测序技术（Illumina MiSeq platform）解析海草不同生长时期下根际与非草区微生物群落特征。结果] 微生物群落结构差异由海草生长时期以及海草是否定植共同驱动。在海草成熟期，丙酸菌属（Propionigenium）在大叶藻与日本鳗草根际有明显富集，其相对丰度分别为11.58%和14.26%；在海草幼苗期，脱硫球茎菌科（Desulfobulbaceae）在海草根际富集（大叶藻：2.299%，日本鳗草：4.092%）；在海草衰退期时，硫卵菌属（Sulfurovum）的相对丰度在根际较高（大叶藻：5.624%，日本鳗草：3.749%）。此外，海草生长时期对不同样品之间微生物群落结构差异的解释度最大（R²=0.20335，P=0.002）。PICRUSt2功能预测结果表明各功能基因在海草不同生长时期所呈现的趋势一致，但丰度上呈现出幼苗期 > 成熟期 > 衰退期的结果。结论] 天鹅湖海草床沉积物微生物群落结构在海草不同生长时期呈现不同的多样性特征，具有明显的根际效应且不同种类海草的根际微生物群落无显著差异，不具有物种特异性。

Rhizosphere microbial community structure and driving mechanism of Zostera marina and Zostera japonica in Swan Lake, Weihai

Objective] This research aims to investigate the diversity of microbial community structure in different seagrass growth periods, and to analyze the internal factors that lead to the differences in microbial community structure.Methods] The rhizosphere sediments of seagrass and unvegetated areas surface sediments were collected. High throughput sequencing (Illumina MiSeq Platform) was used to analyze the microbial community characteristics of rhizosphere and unvegetated areas at different seagrass growth stages.Results] The difference in microbial community structure was driven by the growth period of seagrass and whether seagrass was colonized. At the maturation stage of seagrass, Propionium was significantly enriched in the roots of Z. marina and Z. japonica, with a relative abundance of 11.58% and 14.26%, respectively. In the seedling stage of seagrass, Desulfobulbaceae was enriched at the seagrass roots (Z. marina:2.299%, Z. japonica:4.092%). The relative abundance of Sulfurovum was higher in the rhizosphere during the decline stage of seagrass (Z. marina:5.624%, Z. japonica:3.749%). In addition, the growth period of seagrass had the greatest explanatory power for the differences in microbial community structure (R²=0.20335, P=0.002). The results of PICRUSt2 function prediction showed that all functional genes showed the same trend in different growth stages of seagrass, but the abundance showed the result of seedling stage > mature stage > decline stage.Conclusion] The microbial community structure of seagrass bed sediments in Swan Lake presented different diversity characteristics at different growth stages of seagrass, with obvious rhizosphere effect and no significant difference in the rhizosphere microbial community of different species of seagrass, which was not species-specific.