Paraburkholderia atlantica sp. nov. and Paraburkholderia franconis sp. nov., two new nitrogen-fixing nodulating species isolated from Atlantic forest soils in Brazil

A polyphasic study was conducted with 11 strains trapped by Mimosa pudica and Phaseolus vulgaris grown in soils of the Brazilian Atlantic Forest. In the phylogenetic analysis of the 16S rRNA gene, one clade of strains (Psp1) showed higher similarity with Paraburkholderia piptadeniae STM7183T (99.6%), whereas the second (Psp6) was closely related to Paraburkholderia tuberum STM678T (99%). An MLSA (multilocus sequence analysis) with four (recA, gyrB, trpB and gltB) housekeeping genes placed both Psp1 and Psp6 strains in new clades, and BOX-PCR profiles indicated high intraspecific genetic diversity within each clade. Values of digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) of the whole genome sequences were of 56.9 and 94.4% between the Psp1 strain CNPSo 3157T and P. piptadeniae; and of 49.7% and 92.7% between the Psp6 strain CNPSo 3155T and P. tuberum, below the threshold for species delimitation. In the nodC analysis, Psp1 strains clustered together with P. piptadeniae, while Psp6 did not group with any symbiotic Paraburkholderia. Other phenotypic, genotypic and symbiotic properties were evaluated. The polyphasic analysis supports that the strains represent two novel species, for which the names Paraburkholderia franconis sp. nov. with type strain CNPSo 3157T (= ABIP 241, = LMG 31644) and Paraburkholderia atlantica sp. nov. with type strain CNPSo 3155T (= ABIP 236, = LMG 31643) are proposed.