Isolation And Characterization Of An Antifungal Protein From Black Sesame

Some plants have natural constitutively-expressed genes which encode proteins that confer broad spectrum activity and directly inhibit the growth and development of fungal and bacterial plant pathogens. Isolation and purification of the antimicrobial proteins from plants become more and more important. This has been proven to be a good strategy of plant disease control since the proteins can be developed for use as a novel class of antimicrobial agents and as the basis for making transgenic disease-resistant plants. It is also possible that such genes are safer than induced genes when used in transgenic plants and are thus potentially more acceptable given the current public opposition to genetic modified food.A protein with in vitro antifungal activity was isolated and purified from the seedling of Black Sesame using ion-exchange chromatography (both I{PLC with a POROS.HQ2O column and the ECONO chromatography system with a Q-fast flow column.) and molecular exclusion chromatography. The minimum amount of purified protein required to inhibit 50% of the development of some fungal spores (IC50) varies with different fungi.The protein shows great inhibitory activity against Fusarium oxysporum phaseoli with an IC50 value less than 28 pg/mi and to Collelotrichum gossypii southw~ Trichoderma reesei with larger IC50 value. Even so it doesn show distinct inhibitory activity against Gibberella saubinetii and. Verticillium dahliae klab.The MW, about 3 1KD, was determined by SDS-PAGE. The protein can tolerate the protease digestion but can tolerate high temperatures.To the best of our knowledge, isolation and purification of the antifungal protein from Black Sesame are first reported in present work. Further work is needed in order to know more about the antimicrobial protein.