辣椒根际土壤细菌群落与理化性质互作分析

09Interaction analysis of bacterial communities and physicochemi⁃cal properties in rhizosphere soil of pepper

【目的】分析辣椒根际土壤细菌群落与理化性质的互作,为科学防治辣椒土传病害和辣椒高产优质栽培提供参考依据。【方法】以辣椒苗期、花期和坐果期根际土壤(分别标记为SD、FR和FT)为研究对象,测定3组土壤样本中pH、有机质、总氮、碱解氮、总磷、有效磷、总钾和有效钾含量,采用Illumina HiSeq 2500测序平台进行高通量测序,分析辣椒不同生育期根际土壤细菌Alpha多样性指数及门和属分类水平上相对丰度,通过主坐标分析(PCoA)和基于Bray_Curtis距离的细菌群落不相似性检验,分析辣椒不同生育期根际土壤细菌与理化因子的相关性。【结果】随着辣椒生长,SD、FR和FT三者间的pH和碱解氮含量2个指标具有显著差异(P<0.05,下同);3个生育期土壤细菌的Alpha多样性指数和丰富度、Chao1指数均无显著差异(P>0.05);SD中特有操作分类单元(OTUs)数目最多;3个生育期土壤中变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、酸杆菌门(Acidobacteria)、拟杆菌门(Bacteroidetes)和蓝细菌门(Cyanobacteria)均属于优势菌门;SD根际土壤中链霉菌属(Streptophyta)、嗜酸菌属(Acidovorax)、亚硝化球菌属(Nitrososphaera)和Gp6相对丰度较高,FR根际土壤中链霉菌属、亚硝化球菌属(Nitrososphaera)和红游动菌属(Rhodoplanes)的相对丰度较高,FT以链霉菌属和Trinickia为主。主坐标分析(PCoA)和不相似性检验结果显示,不同生育期根际土壤样本细菌群落之间差异显著。相关分析结果显示,土壤pH和碱解氮与细菌群落呈极显著正相关(P<0.01)。【结论】辣椒根际土壤理化性质及细菌群落结构因生育期不同存在差异,pH和碱解氮是影响细菌群落变化的关键因子。

【Objective】To analyze interaction between pepper rhizosphere soil bacterial community structure and physicochemical properties,which could provide reference for scientific prevention and control of soil-borne diseases and high yield and high quality cultivation of pepper.【Method】In this study,the rhizosphere soils of pepper plants at seedling stage(SD),flowering stage(FR),and fruiting stage(FT)were investigated.The pH,organic matter,total nitrogen,alkaline nitrogen,total phosphorus,available phosphorus,total potassium,and available potassium contents in three soil samples were determined.High-throughput sequencing using the Illumina HiSeq 2500 platform was performed to analyze the bacterial Alpha diversity indexes,relative abundance at phylum and genus levels in the rhizosphere soils of pepper plants at different growth stages.Principal coordinate analysis(PCoA)and dissimilarity analysis based on Bray-Curtis distance was conducted to assess the bacterial communities among different growth stages and the correlation with physicochemical factors.【Result】The results showed significant differences in pH and alkaline nitrogen content among SD,FR and FT as pepper plants grew(P<0.05,the same below).The Alpha diversity indexes,richness and Chao1 index of soil bacterial communities in the three growth stages showed no significant differences(P>0.05).The SD soil had the highest number of unique operational taxonomic units(OTUs).Proteobacteria,Actinobacteria,Acidobacteria,Bacteroidetes,and Cyanobacteria were dominant phyla in the rhizosphere soils of the three growth stages.Streptophyta,Acidovorax,Nitrososphaera and Gp6 had relatively high abundance in the SD rhizosphere soil.Streptophyta,Nitrososphaera and Rhodoplanes had relatively high abundance in the FR rhizosphere soil.Streptophyta and Trinickia were dominant genera in the FT rhizosphere soil.Principal coordinate analysis(PCoA)and dissimilarity analysis revealed significant differences among bacterial communities in rhizosphere soil samples from different growth stages.The correlation analysis showed extremely significant and strong positive correlation between pH and alkaline nitrogen with bacterial communities(P<0.01).【Conclusion】The physical and chemical properties of pepper rhizosphere soil and the structure of bacterial community vary with different growth stages.PH and alkaline nitrogen are key factors influencing the change in bacterial communities.