State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences
the National Key Research and Development Program of China(Nos. 2021YFC3201201, 2021YFD1900602)，the National Natural Science Foundation of China(Nos. 41977015)
辨明盐渍土原核生物群落特征及潜在功能对盐渍化程度和土地利用类型的响应，对理解盐渍土壤元素循环与植物互馈效应、构建良性循环农田生态系统具有重要意义。以河套灌区不同盐渍化程度的农田和荒地为研究对象，结合土壤基本理化性质分析与原核生物高通量测序方法，探究盐渍化土壤中原核生物的群落组成特征、环境驱动要素及其潜在功能。结果表明，农田土壤盐渍化程度显著低于荒地，其原核生物多样性更高，特别是富集了大量农田特有的ASV（扩增子序列变体，amplicon sequence variant）；原核生物的群落组成在农田和荒地间差异最大，并主要受到土壤电导率（EC）、pH和有机质（SOM）等环境因子的驱动。基于群落组成和功能预测的差异分析结果表明，盐渍化农田中具有较高丰度的氮循环相关微生物以及潜在的植物促生菌，如亚硝化球菌（Nitrososphaeraceae）、亚硝化单胞菌（Nitrososmonadaceae）、诺卡氏菌（Nocardioidaceae）和鞘氨醇单胞菌（Sphingomonadaceae）等；而盐渍化荒地富集了以盐杆菌（Halobacterota）为代表的古菌和具有烃类化合物分解功能的原核生物类群。本研究对于明晰北方灌区盐渍土原核生物群落特征与土壤微环境的互馈关系、揭示土壤养分周转对提升土壤-植物-微生物跨域有益协同具有指导意义。
【Objective】 Soil salinization affects the quality of arable land and threatens the sustainable development of agriculture. As an important indicator of soil environment, soil microbes play important roles in driving soil nutrient cycling and maintaining ecosystem productivity. Therefore, deciphering the response of microbial communities and their potential functions to the degrees of soil salinization and land use type is of great significance for understanding the elemental cycling processes and interactions with plants in a saline-affected agroecosystem. 【Method】 In this study, we explored the composition and potential functions of prokaryotic communities and their environmental drivers in saline soils from farmlands and wastelands with different salinization degrees, by combining prokaryotic high-throughput sequencing and soil physicochemical analysis methods in a typical saline area of Hetao Irrigation District of China. 【Result】 Compared with wastelands, the farmlands exhibited a lower soil salinity but a higher content of soil organic matter (SOM) (P < 0.05). In farmlands with different salinity levels, mild saline soil had a significantly higher yield of sunflower than the moderate and severe saline soils. Meanwhile, the saline soils in farmland exhibited a higher prokaryotic α diversity than that in the salinized wasteland, with a large number of unique ASVs (Amplicon sequence variants). The prokaryotic α diversity indexes were positively associated with SOM contents but negatively correlated with soil pH, EC, moisture and bulk density. Non-metric multidimensional scaling (NMDS) analysis based on the β diversity of prokaryotes further indicated that the prokaryotic community was mainly differentiated between farmland and wasteland, followed by the soil salinity level in each land use type. Specifically, the prokaryotic community was dominantly driven by environmental factors including EC, pH and SOM, as suggested by canonical correlation analysis (CCA) and Mantel test. Moreover, the phylum including Acidobacteriota, Chloroflexi, Planctomycetota, Crenarchaeota, and Myxococcota in farmlands showed significantly higher abundance than wastelands, whereas Halobacterota and Bacteroidota showed an opposite trend, with Halobacterota only detectable in wastelands and relative abundance ranging from 10.13% to 39.41%. Through predicting the potential functions of the prokaryotic community, we found that there were high abundances of nitrogen cycling-related microbes like Nitrososphaeraceae and Nitrososmonadaceae, and potential plant growth-promoting bacteria including Nocardioidaceae and Sphingomonadaceae in salinized farmlands. By contrast, the salinized wasteland enriched prokaryotic groups with potential hydrocarbon decomposition function. 【Conclusion】 Our study indicates strong selection effects of different land use types on prokaryotic communities in salinized soil of Hetao Irrigation District, which has important implications for clarifying the feedback between prokaryotic community and physicochemical properties of saline soils, as well as revealing the synergy effect among soil-plant-microorganism for soil nutrient turnover and agricultural sustainability.
ZHANG Lu, YANG Jingsong, YAO Rongjiang, WANG Xiangping, XIE Wenping. The distribution and potential functions of prokaryotic communities in saline soils of Hetao Irrigation District[J]. Acta Pedologica Sinica,,[In Press]