Plant Pathology Group, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH), CH-8092 Zürich, Switzerland.
Syst Appl Microbiol. 2011 May;34(3):180-8. doi: 10.1016/j.syapm.2010.10.005. Epub 2011 Mar 9.
Fluorescent Pseudomonas strains producing the antimicrobial secondary metabolite 2,4-diacetylphloroglucinol (Phl) play a prominent role in the biocontrol of plant diseases. A subset of Phl-producing fluorescent Pseudomonas strains, which can additionally synthesize the antimicrobial compound pyoluteorin (Plt), appears to cluster separately from other fluorescent Pseudomonas spp. based on 16S rRNA gene analysis and shares at most 98.4% 16S rRNA gene sequence identity with any other Pseudomonas species. In this study, a polyphasic approach based on molecular and phenotypic methods was used to clarify the taxonomy of representative Phl(+) Plt(+) strains isolated from tobacco, cotton or wheat on different continents. Phl(+) Plt(+) strains clustered separately from their nearest phylogenetic neighbors (i.e. species from the 'P. syringae', 'P. fluorescens' and 'P. chlororaphis' species complexes) based on rpoB, rpoD or gyrB phylogenies. DNA-DNA hybridization experiments clarified that Phl(+) Plt(+) strains formed a tight genomospecies that was distinct from P. syringae, P. fluorescens, or P. chlororaphis type strains. Within Phl(+) strains, the Phl(+) Plt(+) strains were differentiated from other biocontrol fluorescent Pseudomonas strains that produced Phl but not Plt, based on phenotypic and molecular data. Discriminative phenotypic characters were also identified by numerical taxonomic analysis and siderotyping. Altogether, this polyphasic approach supported the conclusion that Phl(+) Plt(+) fluorescent Pseudomonas strains belonged to a novel species for which the name Pseudomonas protegens is proposed, with CHA0(T) (=CFBP 6595(T), =DSM 19095(T)) as the type strain.
产生抗菌次生代谢物 2,4-二乙酰基间苯三酚（Phl）的荧光假单胞菌菌株在植物病害的生物防治中起着重要作用。一组能够额外合成抗菌化合物吡咯并[1,2-a]嘧啶（Plt）的 Phl 产生荧光假单胞菌菌株，根据 16S rRNA 基因分析，似乎与其他荧光假单胞菌属物种分离，与任何其他假单胞菌属物种最多共享 98.4%的 16S rRNA 基因序列同一性。在这项研究中，基于分子和表型方法的多相方法用于阐明从不同大陆的烟草、棉花或小麦中分离的代表性 Phl(+) Plt(+) 菌株的分类学。Phl(+) Plt(+) 菌株根据 rpoB、rpoD 或 gyrB 系统发育与最接近的系统发育邻居（即来自“丁香假单胞菌”、“荧光假单胞菌”和“绿针假单胞菌”种复合体的物种）分离。DNA-DNA 杂交实验阐明 Phl(+) Plt(+) 菌株形成了一个与丁香假单胞菌、荧光假单胞菌或绿针假单胞菌型菌株不同的紧密基因组种。在 Phl(+) 菌株中，Phl(+) Plt(+) 菌株根据表型和分子数据与产生 Phl 但不产生 Plt 的其他生物防治荧光假单胞菌菌株区分开来。数值分类分析和铁载体型也确定了有区别的表型特征。总之，这种多相方法支持 Phl(+) Plt(+) 荧光假单胞菌菌株属于一个新物种的结论，提议使用保护假单胞菌（Pseudomonas protegens）作为该物种的名称，CHA0(T)（=CFBP 6595(T)，=DSM 19095(T)）作为模式株。
