EXTRACELLULAR POLYSACCHARIDES OF POTATO RING ROT PATHOGEN

Many bacteria, including phytopathogenic ones produce extracellular polysaccharides or exopolysaccharides which are universal molecules. Causal agent of potato ring rot, Clavibacter michiganensis subspecies sepedonicus, secretes exopolysaccharides which role in pathogenesis is poorly investigated. The aim of our research is to ascertain the composition and structure of Clavibacter michiganensis subspecies sepedonicus exopolysaccharides. Exopolysaccharides of Clavibacter michiganensis subspecies sepedonicus are determined to consist of 4-6 anionic and neutral components which have molecular weights from <1 kDa to >700 kDa. Glucose is a major monomer of polysaccharides and arabinose, rhamnose and mannose are minor monomers. Glucose is present in α-Dglucopyranose and β-D-glucopyranose configurations. Calcium is determined to be a component of exopolysaccharides. Components of exopolysaccharides of potato ring rot pathogen are probably capableto associate via calcium ions and other ionic interactions that may result in a change of their physiological activity. Further studies of Clavibacter michiganensis subspecies sepedonicus exopolysaccharides composition and structure can serve a base for the synthesis of their chemical analogues with elicitor action

THE INFLUENSE OF MONOIODACETATE ON THE THERMOTOLERANCE OF Clavibacter michiganensis ssp. sepedonicus AND Saccharomyces cerevisiae

To search the antiseptic agents capable to decontaminate the plants from pathogens the combined effect of moderate heat shock (45oC) and glycolisis inhibitor monoiodoacetate (MIA) on survival of potato pathogen Clavibacter michiganensis ssp. sepedonicus (Cms) and yeast Saccharomyces cerevisiae was studied. Under optimal temperature cultivation (26oC) MIA had no toxic effect on S. cerevisiae but decreased viability of Cms. The lethal effect of MIA significantly increased during heat treatment at 45oC. MIA in the range from 0.1 to 1 mM decreased the thermotolerance of Cms and S. cerevisiae cells in 10-10000 folds in dependence from time of treatment. A minimal concentration of MIA capable to affect the thermotolerance was 0.1 and 0.3 mM for S. cerevisiae and Cms, respectively. The effect of MIA on Cms and yeast survival during heat shock was stronger in logarithmic phase than in stationary ones