Gm-TX, a new toxic protein from soybean (Glycine max) seeds with potential for controlling insect pests.

Abstract A novel toxic protein from Glycine max seeds, named Gm -TX, was purified by combination of differential precipitation with ammonium sulphate, DEAE-cellulose, anhydrotrypsin-sepharose 4B and Superdex 200 HR fast-protein liquid chromatography. Gm -TX is composed of one polypeptide chain of 28 kDa (SDS-PAGE), with p I 5.1–5.2, contains Gm- TX IgG, which was inhibited by mannose. It was devoid of trypsin inhibitory, urease and chitinase activities. Gm -TX was lethal to mice by intraperitoneal route with LD 50 of 4.5 mg/kg. Moreover, it showed dose-dependent insecticidal activity on the major economically important pests Callosobruchus maculatus and Dysdercus peruvianus , producing ca. 50% and 56% mortality when incorporated into artificial diets at a level of 1.16% and 0.25%, respectively. These data indicate that Gm -TX is a candidate protein that could be expressed in genetically transformed plants for improved resistance to insect pests.