Complex effects of selenium-arabinogalactan nanocomposite on both phytopathogen Clavibacter michiganensis subsp. sepedonicus and potato plants

Abstract

A novel selenium nanobiocomposite consisting of X-ray amorphous nanoparticles of red elemental selenium (average size ∼67 nm) uniformly encapsulated into arabinogalactan macromolecules has been synthesized. The effect of this nanobiocomposite and its precursors (pure arabinogalactan and selenium dioxide) on the viability of a phytopathogenic bacterium Clavibacter michiganensis subsp. sepedonicus (Spieck et Kotth.) Skapt et Burkh (C. michiganensis) and potato plants has been investigated in vitro. The bactericidal effects of free selenium dioxide and the nanocomposite obtained from the former (normalized selenium concentration 0.000625%) have been demonstrated. The targeted metabolic (trophic) delivery of antimicrobial selenium nanoparticles to the bacterial cells by the arabinogalactan matrix incorporating the particles was detected in the latter case. The treatment of potato plants with selenium dioxide was found to have a negative effect on peroxidase activity and plant growth. On the contrary, treating the plants with the selenium nanocomposite had no negative effects. Thus, the nanocomposite of elemental selenium and arabinogalactan produced in the present work can be considered a new antimicrobial agent for plant sanitation with minimal side effects.