Structure of the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71T

O-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of plant-growth-promoting rhizobacteria Azospirillum doebereinerae GSF71T and studied by sugar analysis along with 1H and 13C NMR spectroscopy, including 2D 1H,1H COSY, TOCSY, ROESY, 1H,13C HSQC, and HMBC experiments. It was established that the polysaccharide is linear and consists of tetrasaccharide repeating units with the following structure.