Abstract: The toxic substances are isolated and partially purified from culture filtrate of Colletotrichum gloeosporioides. The toxic preparation induces tomato seedling to wilt and stoped growth of Olive Callus following necrosis. Olive protoplasts are obtained from callus and exposured in toxin and subsequently examined survival of protoplast in optical microscope. The sensitivity of callus and protoplast to toxin is different in resistant and susceptible var. and the survival of protoplast from resistant var. "Frandoio" is more two-fold than the protoplast from susceptible var. "Zhongsan 24" during 48hr. At 100mg/ml toxin concentration.