不同季节冬水田紫色土细菌群落的垂直分布规律

Vertical distribution of bacterial community in purple soil of winter-flooded paddy fields in different seasons

摘要:

【背景】土壤细菌对环境变化非常敏感，是土壤环境质量检测的重要指标。【目的】为研究不同季节冬水田紫色土细菌的垂直分布规律，揭示土壤细菌群落结构和物种多样性与土壤环境因子的相互关系。【方法】以冬水田紫色土为研究对象，分别于2020年8月(夏季)和2021年 1月(冬季)采集不同深度土壤样品，对土壤细菌16S rRNA基因进行Illumina MiSeq高通量测序，分析在不同季节细菌群落组成和多样性的垂直分布规律。【结果】冬水田紫色土细菌ACE指数、Chao1指数和Shannon指数均呈现出夏季高于冬季，并且随土层深度增加呈现降低的趋势。冬水田紫色土优势菌门为变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)、硝化螺旋菌门(Nitrospirae)、放线菌门(Actinobacteria)和浮霉菌门(Planctomycetes)，优势菌属为Desulfobacca、Haliangium、Anaeromyxobacter、Candidatus_Omnitrophus和Defluviicoccus。Chloroflexi和Actinobacteria在夏季相对丰度较高，Proteobacteria和Nitrospirae在冬季相对丰度较高；Anaeromyxobacter和Candidatus_Omnitrophus在夏季相对丰度较高，Desulfobacca、Haliangium和Defluviicoccus在冬季相对丰度较高。冗余分析(redundancy analysis，RDA)和环境因子热图分析结果均表明，总氮(total nitrogen，TN)、土壤有机质(soil organic matter，SOM)和土壤氧化还原电位(soil redox potential，Eh)是显著影响紫色水稻土细菌群落的主要因子。【结论】本研究丰富了对冬水田紫色水稻土细菌群落组成和多样性的认识，证实了不同季节冬水田紫色土细菌群落组成和多样性存在差异。

Abstract:

[Background] Soil bacteria are very sensitive to environmental changes and thus are important index of soil environmental quality. [Objective] To study the vertical distribution of soil bacteria in purple soil of winter-flooded paddy fields in different seasons and reveal the relationship between soil bacterial community structure, species diversity and soil environmental factors. [Methods] Purple soil of winter-flooded paddy fields were taken as the research object in this study. Soil samples at different depths were collected in August 2020 (summer) and January 2021 (winter) separately. Illumina MiSeq high-throughput sequencing of 16S rRNA gene of soil bacteria was performed to analyze the vertical distribution of bacterial community composition and diversity in different seasons. [Results] The bacterial ACE index, Chao1 index and Shannon index were higher in summer than in winter, and decreased with the increase of soil layers. The dominant bacterial phylum in purple soil of winter-flooded paddy fields were Proteobacteria, Chloroflexi, Acidobacteria, Nitrospirae, Actinobacteria and Planctomycetes, and the dominant bacterial genera were Desulfobacca, Haliangium, Anaeromyxobacter, Candidatus_Omnitrophus and Defluviicoccus. The relative abundances of Chloroflexi, Actinobacteria, Anaeromyxobacter and Candidatus_Omnitrophus were higher in summer, while those of Proteobacteria, Nitrospirae, Desulfobacca, Haliangium and Defluviicoccus were higher in winter. The redundancy analysis (RDA) and correlation analysis of environmental factors showed that total nitrogen (TN), soil organic matter (SOM) and soil redox potential (Eh) were the main factors that significantly affected the bacterial community structure in purple soil. [Conclusion] This study enriched the understanding of bacterial community composition and diversity in purple soil of winter-flooded paddy fields, and confirmed that there were differences in different seasons.