白及根腐病植株根际土壤微生物群落组成特征分析

分析白及根腐病植株根际土壤微生物群落组成特征,为理解白及根腐病发病机理并针对性开展防治工作提供科学依据。利用Illumina HiSeq高通量测序技术,比较分析白及根腐病与健康植株根际土壤微生物群落结构特征,并对土壤理化性质与酶活性进行定量分析。白及根际土壤中优势真菌为子囊菌门(Ascomycota)和Mortierellomycota,优势细菌为变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)。与健康植株相比,发病白及根际土壤Ascomycota相对丰度显著升高,而Mortierellomycota相对丰度显著降低;镰刀菌属(Fusarium)和白粉菌属(Erysiphe)等致病菌群相对丰度显著升高(P<0.05)。多元统计分析表明,健康与发病白及根际土壤细菌与真菌群落存在明显分化。此外,健康植株根际土壤脲酶、蛋白酶与蔗糖酶活性和有效钾含量较高,pH、有机质、铵态氮与硝态氮含量较低。白及根腐病的发生可能与土壤致病菌相对丰度升高、微生物群落结构变化、酶活性降低、养分失衡等因素有关。

Composition Features of Microbial Community in the Rhizospheric Soil of Bletilla striata with Root Rot

Analyzing the composition features of microbial community in the rhizospheric soil of Bletilla striata with root rot would provide the scientific basis for understanding the microbial mechanisms leading to the root rot of B.striata and taking corresponding prevention and control measures.The Illumina HiSeq high-throughput sequencing was used to compare and analyze the microbial community structure in the rhizospheric soils of root-rot and healthy B.striata.Also,the soil physicochemical properties and enzyme activities were quantitatively analyzed.The dominant fungi were Ascomycota and Mortierellomycota,and the dominant bacteria were Proteobacteria and Bacteroidetes in the rhizospheric soil of B.striata.Compared with the healthy individuals,the relative abundance of Ascomycota significantly increased,while the relative abundance of Mortierellomycota decreased.The relative abundance of pathogenic Fusarium and Erysiphe significantly increased in the rhizospheric soil of root-rot B.striata(P<0.05).Multivariate statistical analyses showed the significant differentiation of bacterial and fungal community in the rhizospheric soils between healthy and root-rot B.striata.In addition,the activities of urease,protease and sucrase,and available potassium content were higher in the rhizospheric soil of healthy individuals;while soil pH and the contents of organic matter,NH₄⁺-N,and NO₃^--N were lower.The root-rot disease of B.striata could be related to the increased relative abundance of pathogenic microorganisms,the changes of microbial community structure,the decreased soil enzyme activity,and the imbalance of plant nutrients.