Cell Wall Galactofuranans and Galactomannan as Chemotaxonomic Characteristics of the Clavibacter Genus and its Species

Abstract

Two types of cell wall glycopolymers of different structure were found in the type strains of two species of phytopathogenic bacteria, Clavibacter insidiosus VKM Ac-1402^T and Clavibacter nebraskensis VKM Ac-1404^T (family Microbacteriaceae, class Actinomycetes). The first type was represented by new, previously undescribed (1→6)-linked β-D-galactofuranans, which in the studied strains differed in the structure of side oligosaccharide chains (the structures are given in the text). The structure of the second glycopolymer, a pyruvate-containing galactomannan, was identical in both strains. The results obtained in this work, together with those published previously, indicate that the presence of the pyruvate-containing galactomannan and galactofuranans (with an identical core structure and different side oligosaccharide substituents) can be considered as a chemotaxonomic trait of the genus Clavibacter, and galactofuranans with di-, tri-, or tetrasaccharide substituents of different composition and structures can serve as chemotaxonomic markers of the species. The data obtained expand our understanding of the structural diversity of natural glycopolymers and structural features of the bacterial cell walls in various taxa and may be of interest for taxonomic studies and the studies aimed at elucidating the molecular mechanisms of interaction between bacteria and plant cells.