三峡库区消落带土壤中携带phoD基因的细菌群落结构特征

Characteristics of Soil phoD-Harbouring Bacteria Community in the Water Level Fluctuation Zone of the Three Gorges Reservoir Area

为研究三峡库区消落带土壤中解磷细菌群落特性,于2021年5月在干流消落带采集了不同高程的土壤样品,分析了土壤的总磷(TP)、无机磷(IP)和有机磷(OP)、酸性磷酸酶(ACP)和碱性磷酸酶(ALP)活性,测定了携带phoD基因的细菌群落结构,并探究其与土壤性能指标的关系。结果表明,消落带土壤中携带phoD基因细菌群落的丰富度随高程的降低而下降(P<0.05),不同高程土壤中的优势门和属排序存在差异;各高程间表现出显著差异的细菌有1门1纲1目4科6属,其中Verrucomicrobia门的一支类群在175 m高程土壤的丰度更高,而Streptosporangiaceae科和Aquisphaera属分别在155 m和165 m的低高程土壤中有更高丰度,可能来源于底层沉积物。Spearman相关性分析表明,携带phoD基因的细菌群落多样性与高程、IP含量显著相关。db-RDA分析表明,TP和IP是主导消落带土壤携带phoD基因的细菌群落结构的环境因子。

To investigate the characteristics of the phosphate-solubilizing bacterial community in the Water Level Fluctuation Zone(WLFZ)of the Three Gorges Reservoir(TGR)Area,soil samples were collected at different altitudes in May,2021.The contents of total phosphorus(TP),inorganic phosphorus(IP)and organic phosphorus(OP),and activities of acidic phosphatase(ACP)and alkaline(ALP)phosphatase were analyzed.The community structure of phoD-harbouring bacteria was determined,and its relationship with soil performance parameters was also investigated.The results showed a significant decline in the richness of the soil phoD-harbouring bacterial community in the WLFZ with decreasing altitudes(P<0.05).Moreover,variations in dominant phyla and genera were observed in soils at different altitudes.Among these,one phylum,one class,one order,four families,and six genera exhibited significant differences between altitudes.A taxon from the phylum Verrucomicrobia exhibited higher abundance in soils at an altitude of 175 m while the family Streptosporangiaceae and the genus Aquisphaera showed higher abundance in soils at altitudes of 155 m and 165 m,respectively,suggesting a potential source from the bottom sediment.Spearman correlation analysis demonstrated a significant correlation between the diversity of the phoD-harbouring bacterial community and altitudes as well as IP contents.Distance-based redundancy analysis(db-RDA)confirmed that TP and IP were the primary environmental factors influencing the structure of the phoD-harbouring bacterial community in the WLFZ of the TGR.