Structural and genetic relationship of the O-antigens of the type strains <I>Azospirillum agricola</I> CC-HIH038 and <I>Azospirillum doebereinerae</I> GSF71

Lipopolysaccharide was isolated from cells of the type strain of rhizobacteria Azospirillum agricola CC-HIH038Т by phenol extraction. O-specific polysaccharide was obtained by mild acid hydrolysis of lipopolysaccharide followed by chromatographic fractionation. On the basis of monosaccharide analysis, including determination of absolute configurations, 1D and 2D 1H and 13C NMR spectroscopy, the following structure of the O-specific polysaccharide repeating unit of A. agricola CC-HIH038T was elucidated: →3)-α-L-Rhap2Ac-(1→3)-α-L-Rhap-(1→3)-α-L-Rhap-(1→3)-β-D-GlcpNAc6Ac-(1→ , which is structurally related to A. doebereinerae GSF71T . Based on the analysis of full-genome sequencing data for strains A. agricola CC-HIH038T and A. doebereinerae GSF71T the O-specific polysaccharide biosynthesis loci were identified, which were characterized by a similar organization and a high level of gene homology, confirming the common structure of the O-antigens of these strains.