PURIFICATION AND CHARACTERIZATION OF TOXINS FROM WHEAT ISOLATES OF Drechslera tritici-repentis, Bipolaris bicolor, AND Bipolaris sorokiniana

Abstract

Low molecular weight metabolites produced by Bipolaris bicolor, Bipolaris sorokiniana, and Drechslera tritici-repentis are considered to be toxins that facilitate disease in wheat cultivars. Several such toxins were isolated from these fungi. Electrophoresis demonstrated bands of proteins that reduced shoot inhibition in susceptible plants but not in resistant plants. Chlorophyll content was reduced during the first 10 hours of light in the susceptible plants and after 18 hours in the resistant plants. The enzyme beta-1,3-glucanase increased in the resistant plants after treatment with toxins, but in the susceptible plants this enzyme decreased compared to the control. This suggests that the toxin was a protein and the susceptible plants needed other mechanisms for induced resistance.