Reclassification of Pseudomonas aurantiaca as a synonym of Pseudomonas chlororaphis and proposal of three subspecies, P. chlororaphis subsp. chlororaphis subsp. nov., P. chlororaphis subsp. aureofaciens subsp. nov., comb. nov. and P. chlororaphis subsp. aurantiaca subsp. nov., comb. nov

Abstract

Pseudomonas chlororaphis, Pseudomonas aureofaciens and Pseudomonas aurantiaca were considered as separate species until 1989, when P. aureofaciens was proposed as a later heterotypic synonym of P. chlororaphis with P. aurantiaca remaining as a separate species. Nevertheless, analysis of the almost complete 16S rRNA gene sequences revealed that the type strain of P. aurantiaca, NCIMB 10068(T), shows gene sequence similarities close to 99.5 % with respect to P. chlororaphis DSM 50083(T) and P. aureofaciens DSM 6698(T). DNA-DNA hybridization experiments among strains of P. aurantiaca, P. chlororaphis and P. aureofaciens showed values higher than 70 %, confirming that they represent members of the same species. The results of fatty acid analysis and phenotypic traits showed that these strains are closely related, although there are some differences among the strains belonging to P. aurantiaca, those from P. chlororaphis and those from P. aureofaciens. All these results confirm the previous reclassification of P. aureofaciens into P. chlororaphis and support the reclassification of P. aurantiaca as a synonym of P. chlororaphis. Phenotypic and molecular data permit the description of three novel subspecies within this last species, for which the following names are proposed: P. chlororaphis subsp. chlororaphis subsp. nov. [with the type strain DSM 50083(T) (=ATCC 9446(T)=NCIMB 9392(T))], P. chlororaphis subsp. aureofaciens subsp. nov., comb. nov. [with the type strain DSM 6698(T) (=ATCC 13985(T)=NCIMB 9030(T))] and P. chlororaphis subsp. aurantiaca subsp. nov., comb. nov. [with the type strain NCIMB 10068(T) (=ATCC 33663(T)=CIP 106718(T))].