可产生铁载体的春兰根内生细菌多样性

Diversity of siderophore-producing endophytic bacteria ofCymbidium goeringii roots

【目的】了解可产生铁载体的春兰根内生细菌的多样性,以便筛选到高效的植物促生细菌。【方法】采用CAS检测法测定了189株春兰根内生细菌产生铁载体的能力,并结合16S rRNA基因系统发育分析对可产铁载体的春兰根内生细菌多样性进行了研究。【结果】从189株春兰内生细菌中筛选到47株可产生铁载体的细菌,占菌株总数的24.9%。16S rRNA基因系统发育分析结果表明,47株细菌分属于4个系统发育类群(Alphaproteobacteria,Betaproteobacteria,Firmicutes,Actinobacteria),17个属的31个种。其中放线菌门为最优势类群(42.6%),芽孢杆菌属(Bacillus)和贪噬菌属(Variovorax)为优势菌属,且贪噬菌属为高产铁载体的主体菌属。另外有2个菌株可能代表两个不同属的新物种。【结论】春兰根中可产生铁载体的内生细菌具有丰富的多样性。

[Objective] In order to obtain the effective plant growth-promoting bacteria,we studied the diversity of siderophore-producing endophytic bacteria in the roots of Cymbidium goeringii.[Methods]We screened for siderophore-producing bacteria from 189 root endophytic strains of Cymbidium goeringii by using chrome azurol S（CAS） agar plate assay.The diversity of siderophore-producing endophytic bacteria was investigated by 16S rRNA gene sequence analysis.[Results]We obtained 47 siderophore-producing strains（24.9% of the total strains）.Sequence analysis revealed that 47 strains were members of 31 species of 17 genera in four phylogenetic groups（Alphaproteobacteria,Betaproteobacteria,Firmicutes,Actinobacteria）.The dominant group was Actinobacteria（42.6%）,and the dominant genera were Bacillus and Variovorax.The strains of Variovorax produced relatively high levels of siderophore.In addition,there may be two novel taxonomic units.[Conclusion]The results show that there are abundant species diversity of siderophore-producing endophytic bacteria in the roots of Cymbidium goeringii.