Paraburkholderia simonii sp. nov. and P. youngii sp. nov. – Brazilian and Mexican Mimosa-associated rhizobia. Taxonomic characterization of Paraburkholderia tuberum-like rhizobia from diverse legumes

Previous studies have recognized South American Mimosa legumes as reservoirs of various Paraburkholderia species; several of which have recently been validly named, i.e., P. nodosa, P. symbiotica, P. caballeronis, P. diazotrophica and P. mimosarum. There is however a number of diverse Paraburkholderia strains associated with these legume hosts, which have an unclear taxonomic status. In this study, for instance we focus on 31 of these Paraburkholderia strains which associate with Brazilian and Mexican Mimosa hosts, which were initially identified as P. tuberum or P. tuberum-like based on 16S rRNA sequencing. The evolutionary relatedness of these isolates to type strains of validly named Paraburkholderia species was established with genealogical concordance analysis (of atpD, gyrB, acnA, pab and 16S rRNA phylogenies), Average Nucleotide Identity (ANI), DNA G+C content ratios and phenotypic characteristics. Genealogical concordance delineated two unique species clusters which are new to Science. ANI values (<95%) confirmed these two clusters as unique entities, thus providing further evidence for describing these as novel species. We propose the names Paraburkholderia simonii sp. nov. with type strain JPY169T and Paraburkholderia youngii sp. nov. with type strain JPY251T.