Spread of Beet Necrotic Yellow Vein Virus (BNYVV) and Polymyxa betae in Rhizamania-Resistant and -susceptible sugar beet

The spread of BNYVV in P. betaefBNYVV -infected sugarbeet was directly monitored by ELISA and tissue print immuno blot detection, whilst that of P. betae was indirectly monitored using the zoospore antagonist Bacillus subtilis. These studies revealed· a fungus-related component of rhizomania resistance in one Gennan sugarbeet variety. Nucleic acid based P. betae detection methods have also been developed for direct detection of fungus development. It was shown that quantitative development and distribution of P .. betae in roots could be followed by dot blot hybridization and tissue print hybridization blotting respectively. BNYVV detection methods can now be complemented by P. betae detection methods, making it possible to differentiate between virus- and fungus-related rhizomania resistance mechanisms in sugarbeet varieties