Burkholderia symbiotica sp nov., isolated from root nodules of Mimosa spp. native to north-east Brazil

Four strains, designated JPY-345(T), JPY-347, JPY-366 and JPY-581, were isolated from nitrogen-fixing nodules on the roots of two species of Mimosa, Mimosa cordistipula and Mimosa misera, that are native to North East Brazil, and their taxonomic positions were investigated by using a polyphasic approach. All four strains grew at 15-43 degrees C (optimum 35 degrees C), at pH 4-7 (optimum pH 5) and with 0-2% (w/v) NaCl (optimum 0% NaCl). On the basis of 16S rRNA gene sequence analysis, strain JPY-345(T) showed 97.3% sequence similarity to the closest related species Burkholderia soli GP25-8(T), 97.3% sequence similarity to Burkholderia caryophylli ATCC25418(T) and 97.1% sequence similarity to Burkholderia kururiensis KP23(T). The predominant fatty acids of the strains were C-18:1 omega 7c (36.1 %), C-16:0 (19.8%) and summed feature 3, comprising C-16:1 omega 7c and/or C-16:1 omega 6C (11.5%). The major isoprenoid quinone was Q-8 and the DNA G+C content of the strains was 64.2-65.7 mol%. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and several uncharacterized aminophospholipids and phospholipids. DNA-DNA hybridizations between the novel strain and recognized species of the genus Burkholderia yielded relatedness values of <51.8%. On the basis of 16S rRNA and recA gene sequence similarities and chemotaxonomic and phenotypic data, the four strains represent a novel species in the genus Burkholderia, for which the name Burkholderia symbiotica sp. nov. is proposed. The type strain is JPY-345(T) (=LMG 26032(T)=BCRC 80258(T)=KCTC 23309(T)).