微藻配施枯草芽孢杆菌对烟田土壤化学性质和细菌群落的影响

Effects of microalgae combined with Bacillus subtilis on soil chemical properties and bacterial communities in tobacco fields

【目的】研究微藻与枯草芽孢杆菌的共生关系及其对土壤细菌群落的影响。【方法】设置微藻(M)、枯草芽孢杆菌(B)、微藻和枯草芽孢杆菌(MB)及空白对照(CK)4个处理,在室内连续恒温培养35 d,测定土壤化学性质,运用荧光定量PCR和Illumina Miseq测序等分子生物学技术,分析土壤细菌群落丰度和组成的演替规律,揭示微藻配施枯草芽孢杆菌对土壤化学性质和细菌群落的影响。【结果】与CK处理相比,微藻配施枯草芽孢杆菌显著提高土壤铵态氮、硝态氮、DOC含量和pH,在培养第35天分别增加11.93%、17.80%、5.58%和2.75%。微藻配施枯草芽孢杆菌显著增加土壤细菌群落丰富度和多样性,改善土壤细菌群落结构,显著增加变形菌门(Proteobacteria)、硝化螺旋菌属(Nitrospira)和芽孢杆菌属(Bacillus)的相对丰度。冗余分析(RDA)结果显示,土壤pH、有效磷和硝态氮含量是引起土壤细菌群落结构变化的主要环境因子。微藻配施枯草芽孢杆菌促进土壤细菌群落间的正向相互作用,显著增加网络拓扑参数节点数、边数、平均度,网络更加复杂。【结论】微藻配施枯草芽孢杆菌能有效改良土壤养分,调节养分变化规律,显著增加土壤细菌多样性,优化土壤细菌群落结构,促进细菌群落间的相互作用。

[Objective]This study aims to investigate the symbiotic relationship between microalgae and Bacillus subtilis and their impact on soil bacterial communities.[Method]Four treatments,including microalgae,Bacillus subtilis,microalgae and Bacillus subtilis,and blank control,were designed.They were continuously cultured at constant temperature in room for 35 days.Soil chemical properties were determined.Using molecular biology techniques such as fluorescence quantitative PCR and Illumina Miseq sequencing,the succession rules of soil bacterial community abundance and composition were analyzed,and the effects of microalgae combined with Bacillus subtilis on soil chemical properties and bacterial community were revealed.[Result]Compared with CK treatment,microalgae combined with Bacillus subtilis significantly increased the contents of ammonium nitrogen,nitrate nitrogen,DOC and pH in soil,which increased by 11.93%,17.80%,5.58%and 2.75%respectively on the 35th day of culture.Microalgae combined with Bacillus subtilis significantly increased the richness and diversity of soil bacterial community,improved the structure of soil bacterial community,and significantly increased the relative abundance of Proteobacteria,Nitrospira and Bacillus.Redundancy analysis(RDA)showed that soil pH,available phosphorus and nitrate nitrogen content were the main environmental factors that caused the change of soil bacterial community structure.Microalgae combined with Bacillus subtilis promoted the positive interaction between soil bacterial communities,significantly increased the number of nodes,edges and average degree of network topological properties,and made the network more complex.[Conclusion]The combination of microalgae and Bacillus subtilis can effectively improve soil nutrients,regulate nutrient changes in the soil,significantly increase soil bacterial diversity,optimize soil bacterial community structure,and promote interactions between bacterial communities.