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Rhamnomannans and Teichuronic Acid from the Cell Wall of Rathayibacter tritici VKM Ac-1603T

A. S. Shashkov1, E. M. Tul’skaya2,a*, G. M. Streshinskaya2, A. S. Dmitrenok1, N. V. Potekhina2, S. N. Senchenkova1, N. F. Piskunkova2, L. V. Dorofeeva3, and L. I. Evtushenko3

1Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia

2Lomonosov Moscow State University, Faculty of Biology, 119991 Moscow, Russia

3All-Russian Collection of Microorganisms (VKM), Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia

* To whom correspondence should be addressed.

Received November 28, 2019; Revised December 18, 2019; Accepted December 18, 2019
The structures of three cell wall glycopolymers of the phytopathogen Rathayibacter tritici VKM Ac-1603T (family Microbacteriaceae, order Micrococcales, class Actinobacteria) were established by chemical methods and NMR spectroscopy. Polymer 1 is a branched rhamnomannan with the repeating unit →3)-α-[β-D-Xylp-(1→2)]-D-Manp-(1→2)-α-D-Rhap-(1→3)-α-D-Manp-(1→2)-α-D-Rhap-(1→; polymer 2 is a linear rhamnomannan with the repeating unit →2)-α-D-Manp-(1→2)-α-D-Rhap-(1→3)-α-D-Manp-(1→2)-α-D-Rhap-(1→; polymer 3 is a branched teichuronic acid containing monosaccharide residues GlcA, Gal, Man, and Glc at a 1 : 1 : 1 : 5 ratio (see the text for the structures). It has been demonstrated that representatives of four Rathayibacter species studied to date (R. tritici VKM Ac-1603T, R. iranicus VKM Ac-1602 T, R. toxicus VKM Ac-1600 and “Rathayibacter tanaceti” VKM Ac-2596) contain differing patterns of phosphate-free glycopolymers. At the same time, the above Rathayibacter strains have a common property — the presence of rhamnomannans with D-rhamnose. These rhamnomannans may be linear or branched and differing in the positions of glycosidic bonds and side substituents. The presence in the cell wall of rhamnomannans with D-rhamnose may serve as useful chemotaxonomic marker of the genus Rathayibacter.
KEY WORDS: Rathayibacter, cell wall, rhamnomannan, teichuronic acid, D-rhamnose, NMR spectroscopy

DOI: 10.1134/S0006297920030128