METHODS: Marshlands with four types of land use were selected along the Yangtze River basin on April 2021, including poplar forest-crops integrated planting, reed areas, agricultural cultivation lands and ditches. The distribution of snails and physicochemical properties of soil were investigated in marshlands with different types of land use, and the V3 to V4 regions of the bacterial 16S ribosomal RNA (16S rRNA) gene, fungal internal transcribed spacer-1 (ITS1) gene and algal ribulose-bisphosphate carboxylase (rbcL) gene in soils were subjected to high-throughput sequencing. The occurrence of frames with living snails and density of living snails were compared in marshland with different types of land use. The associations of soil microorganisms and physicochemical properties with the density of living snails were examined using Pearson correlation analysis, and the contributions of soil microorganisms and physicochemical properties to the density of living snails were evaluated using variance partitioning analysis.
RESULTS: In marshlands with four types of land use, the greatest occurrence of frames with living snails [(4.94 ± 2.14)%] and density of living snails [(0.070 ± 0.026) snails/0.1 m2] were seen in ditches, and the lowest were found in [(1.23 ± 1.23)%] agricultural cultivation lands [(0.016 ± 0.019) snails/0.1 m2]. A total of 2 phyla, 5 classes, 8 orders, 9 families and 11 genera of algae were detected in soils at four types of land use, with Chlorophyta as the dominant phylum and Pseudoneochloris as the dominant genus. A total of 44 phyla, 134 classes, 281 orders, 338 families and 516 genera of bacteria were detected in soils at four types of land use, with Proteobacteria and Acidobacteriota as the dominant phyla and uncultured Acidobacterium, MND1, Mitrospira, Haliangium and Sphingomonas as dominant genera. A total of 11 phyla, 41 classes, 108 orders, 223 families and 408 genera of fungi were detected in soils at four types of land use, with phyla Ascomycota, Basidiomycota and Mortierellomycota presenting high relative abundances and genera Cladorrhinum, Mortierella and Humicola presenting high relative abundances. Pearson correlation analysis revealed that the density of living snails correlated negatively with the relative abundance of Proteobacteria (r = -0.965, P < 0.05) and soil electronic conductivity (r = -0.962, P < 0.05) and positively with soil moisture (r = 0.951, P < 0.05). Variance partitioning analysis demonstrated that the physicochemical properties and microorganisms of soil contributed 69% and 10% to the density of living snails, respectively.
CONCLUSIONS: The diversity of microbial communities varies in soils at different types of land use in marshland along the Yangtze River basin, and the physicochemical properties and microorganisms of soils may affect the distribution of O. hupensis snails.
[摘要] 目的 调查长江滩地不同土地利用类型土壤微生物群落、理化性质及钉螺分布特征, 探索土壤微生物与理化性 质对钉螺分布的影响, 从而为长江滩地抑螺防病提供科学依据。方法 2021 年 4 月选取杨农复合、芦苇地、农业耕地、沟 渠 4 种土地利用类型长江滩地为研究对象, 调查不同土地利用类型滩地钉螺分布、土壤理化性质, 对土壤中细菌 16S 核糖 体 RNA (16S ribosomal RNA, 16S rRNA) 基因 V3 ~ V4 区、土壤中真菌内转录间隔区 1 (internal transcribed spacer-1, ITS1) 基 因、土壤中藻类核酮糖二磷酸羧化酶 (ribulose-bisphosphate carboxylase, rbcL) 基因进行高通量测序。比较不同土地利用 类型滩地活螺框出现率和活螺密度, 采用 Pearson 相关性分析探究土壤微生物、理化性质与活螺密度间的关系, 采用方差 分解分析估算土壤微生物、理化性质对活螺密度的贡献率。结果 不同土地利用类型滩地中, 沟渠活螺框出 现率 [(4.94 ± 2.14) %] 和活螺密度 [(0.070 ± 0.026) 只/0.1 m2] 最高, 农业耕地活螺框出现率 [(1.23 ± 1.23) %] 和活螺密度 [(0.016 ± 0.019) 只/0.1 m2] 最低。在不同土地利用类型土壤中共检测到 2 个门、5 个纲、8 个目、9 个科、11 个属藻类, 其中 绿藻门为优势藻门、拟新绿藻属为优势藻属; 在不同土地利用类型土壤中共检测到 44 个门、134 个纲、281 个目、338 个 科、516 个属细菌, 其中变形菌门、酸杆菌门为主要优势菌门, 未培养的酸杆菌属、MND1 属、硝化螺旋菌属、赭黄嗜盐囊菌 属、鞘氨醇单胞菌属为优势菌属; 在不同土地利用类型土壤中共检测到 11 个门、41 个纲、108 个目、223 个科、408 个属真 菌, 其中子囊菌门、担子菌门、被孢霉门相对丰度较高, 枝鼻菌属、被孢霉属、腐质霉属相对丰度较高。Pearson 相关性分 析显示, 活螺密度与变形菌门相对丰度 (r = −0.965, P < 0.05) 及土壤电导率 (r = −0.962, P < 0.05) 呈显著负相关、与土壤 含水量呈显著正相关 (r = 0.951, P < 0.05)。方差分解分析结果表明, 土壤理化性质、微生物对活螺密度贡献率分别为 69% 和 10%。结论 长江滩地不同土地利用类型土壤中微生物群落多样性存在差异, 土壤微生物与理化性质可影响钉螺分布。.