Purification and partial characterization of a phytotoxin produced by sarocladium oryzae, the rice sheath rot pathogen: Reinigung und partielle charakterisierung eines vom reisblattscheidenfäule-pathogen sarocladium oryzae erzeugten phytotoxins

An extracellular, hydrophilic, thermostable phytotoxin was purified to homogeneity from culture fluids of Sarocladium oryzae and sheath rot infected rice plants. The phytotoxin was purified by solvent extraction, gel filtration on Sephadex G-75 and HPLC. Toxicity was evaluated with detached leaf sheath and electrolyte leakage bioassays. Purified phytotoxin induced visible symptoms of the disease, when applied to rice sheath even at a low concentration of 5 μg. The toxin is a glycoprotein with carbohydrate as major component. The importances of the carbohydrate moiety for toxic activity was indicated by inactivation of toxic compound after periodate oxidation. The toxin caused lesions on a number of other monocots and dicots and proved to be non-host specific. This is the first report of the purification and characterization of S. oryzae toxin from in vitro and in vivo and we propose its name SO-toxin.