植物根际促生菌的筛选及鉴定

Screening and identification of plant growth-promoting rhizobacteria

【目的】植物根际促生菌(PGPR)和植物的互作关系往往不稳定,PGPR菌群有可能提高菌株对野外环境的适应性。为此,本文根据PGPR促生机制的多样性,从不同植物根际土壤进行了PGPR的筛选及鉴定。【方法】首先,按照固氮、解磷、解钾、拮抗6种常见病原真菌,同时能在植物根际定殖为基本初筛标准,然后在实验室条件下测定初筛菌株的多项促生能力(PGP),最后通过生理生化试验和16SrRNA基因序列分析对所筛菌株进行鉴定。【结果】从江苏扬州、盐城等地土壤样品筛选出14株PGPR,具有体外抑菌、产NH3、产IAA、产HCN、产嗜铁素、解磷、溶钾、固氮以及产抗生素等促生能力。分类鉴定结果显示:7株属于假单胞菌属(Pseudomonas)、3株属于类芽孢杆菌属(Paenibacillus)、2株为芽孢杆菌属(Bacillus)、1株为布克霍尔德氏菌属(Burkholderia)、1株为欧文氏菌属(Erwinia)。【结论】所筛细菌具有多种促生能力,且能在根际定殖,为进一步构建多功能PGPR广适菌群提供菌株资源。

[Objective]The interaction between plant growth promoting rhizobacteria （PGPR） and plants can be unstable,PGPR with PGP activities may be well adapted to particular soil environment.Based on this,we isolated and identified PGPRs from different rhizosphere soils according to their multiple mechanisms.[Methods] Preliminary screening of PGPRs under the premises of PGPR may having the abilities of N2-fixing,phosphate and potassium solubilization,and resistance against six common pathogenic fungi as well as rhizosphere colonization.After that,multiple PGP activities were detected in vitro.Finally,PGPRs were classified and identified by combining physiological and biochemical tests and 16S rRNA gene sequence analysis.[Results]Fourteen strains having various mechanisms of PGP activities such as NH3,IAA,HCN,siderophore,antibiotics production,phosphate and potassium solubilization,and N2-fixing were isolated from different rhizosphere soils in Yangzhou and Yancheng,Jiangsu province.These 14 isolates could be identified as Pseudomonas （7 isolates）,Paenibacillus （3 isolates）,Bacillus （2 isolates）,Burkholderia （1 isolate） and Erwinia （1 isolate）.[Conclusion]Isolates with multiple PGP activities can also be rhizospheric competent,able to survive and colonize in the rhizosphere,providing promising isolates for PGPRs combination to resolve the challenges in field application of PGPR.