三七连作根际土壤微生物区系的16S rRNA系统遗传多样性

Microbial distribution and 16S rRNA diversity in the rhizosphere soil of Panax notoginseng

摘要:

摘要:【目的】针对三七连作土传病害的生物防治技术研究，探讨其根际土壤微生物多样性与根腐病害的关联性。【方法】采集三七连作6年的健康植株与根腐病植株根际土壤，采用多种培养基进行分离、纯化，并对分离菌株提取DNA，用其16S rRNA序列的通用引物进行PCR扩增，进行Blast同源及其系统进化树分析。【结果】从采集样品中分离出的菌株分布于细菌域(Bacteria)中的4个门(Phyla) 共40个属(Genera)，其中从健康植株组土壤中培养出179株菌，分布于30个属，以伯克氏菌属(Burkholderia)、节杆菌属( Arthrobacter)、链霉菌属(Streptomyces)及芽孢杆菌属(Bacillus)为优势菌群;根腐病株组土样共培养出117株菌，分布于29个属，以罗尔斯顿菌属(Ralstonia———病原菌)、单胞菌属(Sphingomonas)、寡养单胞菌属(Stenotrophomonas)等为优势菌群;其中黄杆菌属(Flavobacterium)、肠杆菌属(Enterobacter)的分离菌株仅从病株组土壤中分离到;发现其可能新种5株;健康组与根腐病组土壤EC值及各元素离子浓度差异明显(P＜0.05)，健康组土壤中的优势微生物种群分布与土样中的EC值、NO－3、SO2－4、CO2－3、K+及全盐量呈负相关关系(显著度P＜0.01)。【结论】研究表明，诱导三七连作土传病害的发生，除病原菌作用影响外，还与土壤理化性质和土壤微生物的种群结构及其优势微生物的种群比例具有密切的关联性，特别是土壤中有益微生物(Burkholderia，Bacillus，Streptomyces 等)的丰度，对评价三七土壤健康状况及病害防治预报具有重要的指导意义。

关键词:关键词:三七，根腐病害，土壤微生物，多样性分析，土壤理化性质

Abstract:

Abstract:［Objective］We studied the correlation between the microbial diversity in Panax notoginseng root soil and its root rot diseases，to find biological control approaches in Panax notoginseng soil borne diseases.［Methods］We isolated bacterial strains from the rhizosphere soils of healthy and root rot Panax notoginseng plants that are cultured continuously for 6 years in Wenshan Region．After separation and purification，we obtained DNA．On the basis of 16S rRNA’s general primer we carried out PCR amplification，conducted blast gene similarity and analyzed phylogenetic information． ［Results］The isolated bacterial strains distributed to 4 phyla，40 genera of bacteria，179 isolates from the samples of healthy Panax notoginseng rhizosphere soil belong to 30 genera and Burkholderia，Arthrobacter，Streptomyces and Bacillus are the dominant microflora．Additionally，117 isolates from the samples of root rot Panax notoginseng rhizosphere soil belong to 29 genera and Ralstonia，Sphingomonas，Stenotrophomonas as the dominant microflora．Among them，Flavobacterium and Enterobacter were only isolated from the samples of root rot Panax notoginseng rhizosphere soil．At least 5 isolates are novel species; the ions concentration and electrical conductivity value show distinct discrepancy between the two groups (P＜0.05);the microbial amount of dominant species in the healthy soil samples present negative correlation with electrical conductivity value，the concentration of NO3－，SO42－，CO32－，K+ and total salt (P＜0.01)．［Conclusion］In addition to pathogen infection，the physical and chemical characteristics，microbial community structure and the proportion of dominant species are also closely related to notoginseng continuous cropping soil borne disease．Especially the beneficial microorganisms (Burkholderia，Bacillus，Streptomyces，etc.) abundance is significant to evaluate the soil healthy condition and accurately disease control ＆ forecast for Panax notoginseng cultivation.

Key words:Keywords: Panax notoginseng，root rot，soil microbes，diversity analysis，physical-chemical characteristics of soil