The invention relates to isolated DNA sequences encoding MF3 polypeptides that induce multiple resistance in plants toward a variety of viral and microbial infections and against pests and a method of obtaining transgenic plants expressing MF3 polypeptides. The invention also relates to a method of isolating and purifying an MF3 polypeptide from bacterial cells expressing the polypeptide and its use as a plant protectant with or without carrier agent.