Symbiotic and non-symbiotic Paraburkholderia isolated from South African Lebeckia ambigua root nodules and the description of Paraburkholderia fynbosensis sp nov.

Nine Gram-negative, rod-shaped bacteria were isolated from Lebeckia arnbigua root nodules. All strains were able to nodulate and fix nitrogen with Lebeckia arnbigua apart from WSM4178(T), WSM4181 and WSM4182. Based on the 16S rRNA gene phylogeny, all strains were closely related to Paraburkholderia species (98.4-99.9%), belonging to the Betaproteobacteria class and Burkholderiaceae family. According to 16S rRNA gene phylogeny the closest relative for WSM4174-WSM4177 and WSM4179-WSM4180 was Paraburkholderia tuberum (99.80-99.86 %), for WSM4178(T) was Paraburkholderia caledonica (98.42 %) and for WSM4181-WSM4182 was Paraburkholderia graminis (99.79 %). Analysis of the gyrB and recA housekeeping genes supported the assignment of WSM4181-WSM4182 to P. graminis and the other investigated strains could be assigned to the genus Paraburkholderia. The results of DNA-DNA hybridization, physiological and biochemical tests allowed genotypic and phenotypic differentiation of WSM4178(T) from the closest validly published Paraburkholderia species. However, WSM41 74-WSM41 77 and WSM41 79-WSM4180 could not reliably be distinguished from its closest neighbour and therefore complete genome comparison was performed between WSM4176 and P. tuberum STM678(T) which gave ANI values of 96-97 %. Chemotaxonomic data, including fatty acid profiles and quinone data supported the assignment of the strains to the genus Paraburkholderia. On the basis of genotypic and phenotypic data one novel species, Paraburkholderia fynbosensis sp. nov. (WSM4178(T)=LMG 27177(T)=HAMBI 3356(T)), is proposed and the isolation of P. tuberum and P. graminis from root nodules of Lebeckia arnbigua is reported.