The structure of the lipooligosaccharide from Xanthomonas oryzae pv. Oryzae: the causal agent of the bacterial leaf blight in rice

•The complete structure of Xanthomonas oryzae pv. oryzae (Xoo) has been elucidated.•The core structure is similar to that expressed by X. campestris pv. campestris LOS.•The Xoo LOS lipid A revealed novel features compared to others from Xanthomonas genus.•Both Xoo LOS and lipid A highlighted a potent immunostimulant activity on rice cells.

The structure of the lipooligosaccharide (LOS) from the rice pathogen Xanthomonas oryzae pv. oryzae has been elucidated. The characterization of the core oligosaccharide structure was obtained by the employment of two chemical degradation protocols and by analysis of the products via NMR spectroscopy. The structure of the lipid A portion was achieved by MALDI mass spectrometry analysis on purified lipid A. The LOS from Xanthomonas oryzae pv. oryzae revealed to possess the same core structure of Xanthomonas campestris pv. campestris and interesting novel features on its lipid A domain. The evaluation of the biological activity of both LOS and isolated lipid A was also executed.

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