牡丹野生种根际土壤细菌群落特征分析

Analysis of bacterial community characteristics in the rhizosphere soil of wild tree peony

【目的】植物根际微生物群落由土壤环境和根系代谢活动共同作用产生,在植物生长发育过程中发挥重要功能。解析牡丹野生种在引种地根际土壤细菌群落特征,对有效利用微生物资源和保护野生植物种质资源具有重要的理论意义,为改良牡丹野生种的土壤环境、实现优质种质资源广谱性种植奠定基础。【方法】应用MiSeq高通量测序技术对大花黄牡丹(Paeonia ludlowii)、狭叶牡丹(P.potaninii)、紫牡丹(P.delavayi)、黄牡丹(P.lutea)、紫斑牡丹(P.rockii)、杨山牡丹(P.ostii)、四川牡丹(P.decomposita)、稷山牡丹(P.jishanensis)和卵叶牡丹(P.qiui)9个牡丹野生种根际土壤样品进行16S rRNA基因测序,并分析其与理化指标的相关性。【结果】高通量测序共获得606 536条序列和99个OTU聚类,隶属于24门、84纲、154目、280科和603属。Alpha多样性分析表明杨山牡丹根际微生物群落包含的物种数目最高,Beta分析发现四川牡丹、紫斑牡丹、黄牡丹、杨山牡丹、紫牡丹和大花黄牡丹根际土壤中细菌群落结构更为相似。细菌群落组成分析结果表明:根际土壤样本的核心优势细菌群落主要由变形菌门(Proteobatteria)、酸杆菌门(Acidobacteria)、放线菌门(Actinobacteria)和绿弯菌门(Chloroflexi)组成。酸杆菌门、绿弯菌门、硝化螺旋菌门(Nitrospirae)、芽单胞菌门(Gemmatimonadetes)、亚硝化螺菌属(Nitrosospira)和假单胞菌属(Pseudomonas)等有益菌种在不同野生种中存在显著差异。根际细菌群落功能预测多集中在代谢、遗传信息处理和环境信息处理方面。牡丹野生种根际细菌群落受土壤有机质和速效钾含量影响较大。【结论】不同野生种根际土壤细菌群落结构不同,细菌群落的形成与牡丹种类存在显著相关性,有益菌门/属的富集,对植株生长具有促进作用。今后可有效利用根际微生物资源以改良牡丹野生种的土壤环境,实现优质种质资源广谱性种植,为野生种质资源的保护奠定基础。

【Objective】The microbial community in the rhizosphere is produced by the interactions of the soil environment and root metabolic activities,and plays an important role in plant growth and development.Analysis of characteristics of bacterial community in the rhizosphere soil of wild tree peony species possesses important theoretical significance for the effective use of microbial resources to protect wild plant germplasm resources and lays a foundation for improving the soil environment of wild tree peony species and realizing the broad⁃spectrum planting of high⁃quality germplasm resources.【Method】In the present study,MiSeq high⁃throughput sequencing technology with 16S rRNA genes was employed to investigate bacterial community characteristics in the rhizosphere soil of nine wild tree peony species(Paeonia ludlowii,P.potaninii,P.delavayi,P.lutea,P.rockii,P.ostii,P.decomposita,P.jishanensis and P.qiui)as well as their relevance with physicochemical properties.【Result】A total of 606536 sequences and 99 OTU clusters were obtained by high⁃throughput sequencing,which belonged to 24 phyla,84 classes,154 orders,280 families and 603 genera.Alpha diversity analysis revealed that the rhizosphere microbial community of P.ostii contained the highest number of species.Beta analysis revealed that the bacterial community structures in the rhizosphere soils of P.decomposita,P.rockii,P.lutea,P.ostii,P.delavayi and P.ludlowii were similar.Analysis of bacterial community compositions showed that the core and dominant bacteria in the rhizosphere soil were Proteobacteria,Acidobacteria,Actinobacteria and Chloroflexi.Significant differences were found in beneficial bacteria among different wild tree species,such as Acidobacteria,Chloroflexi,Nitrospirae,Gemmatimonadetes,Nitrosospira and Pseudomonas.Predicted functions of the rhizosphere bacterial community have mostly focused on metabolism,genetic information processing,and environmental information processing.The bacterial community in the rhizosphere of wild peony trees is significantly affected by soil organic matter and available potassium.【Conclusion】These results indicated that the bacterial community structure in the rhizosphere soil of different wild tree peony species was different,and the formation of a bacterial community was closely related to the varieties of tree peony.The enrichment in beneficial bacteria(genera)promoted plant growth.In the future,rhizospheric microbial resources could be effectively utilized to improve the soil environment of wild tree peonies,to realize the broad⁃spectrum planting of high⁃quality germplasm resources,and to lay the foundation for the protection of wild planting resources.