Nitrogen-fixing bacterium Burkholderia brasiliensis produces a novel yersiniose A–containing O-polysaccharide

Abstract

Burkholderia brasiliensis, a Gram-negative diazotrophic endophytic bacterium, was first isolated from roots, stems, and leaves of rice plant in Brazil. The polysaccharide moiety was released by ammonolysis from the B. brasiliensis lipopolysac-charide (LPS), allowing the unambiguous characterization of a 3,6-dideoxy-4-C-(1-hydroxyethyl)-D-xylo-hexose (yersiniose A), an uncommon feature for Burkholderia LPS. The complete structure of the yersiniose A–containing O-antigen was identi-fied by sugar andmethylation analyses andNMRspectroscopy. Our results show that the repeating oligosaccharide motif of LPS O-chain consists of a branched tetrasaccharide with the following structure:!2-a-D-Rhap-(1!3)-[a-YerAp-(1!2)]-a-D-Rhap-(1!3)-a-D-Rhap-(1!. Key words: Burkholderia/lipopolysaccharide/ nitrogen-fixing bacterium/yersinios