Abstract: 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.

Abstract: The object of the invention is a protein, termed MF3, or a functional derivative thereof with a novel structure that surprisingly can induce multiple resistance in plants toward a variety of viral and microbial infections and against pests. The invention also concerns an isolated DNA sequence encoding MF3 protein, as such, or as a part of any DNA sequence, or a fragment thereof, or DNA sequences which have degenerate codons with respect to the DNA sequence defined above. The invention also concerns a method of isolating and purifying the protein MF3 from bacterial cells expressing the said protein and its use as a plant protectant with or without carrier agent. Furthermore, the invention concerns a method of obtaining transgenic plants expressing said protein. A further object of the invention is the use of the protein, or of compositions containing the same, as a plant protectant, biopesticide for inducing resistance of plants to viral, microbial phytopathogens and pests.

Abstract: The present invention provides bacterial strains for secretion of soluble biologically active recombinant heterologous proteins into periplasm or on a surface/into a cultivation medium of bacteria. The invention exploits the secretion system of Gram-negative bacteria including periplasmic chaperones and usher/secretin proteins. For accomplishing the aim, the bacterial strains simultaneously express the fusion protein (signal peptide)-(mature hecterologous protein)-(subunit of a bacterial surface structure, Caf1), periplasmic chaperone specific for the subunit, and outer membrane usher/secretin protein specific for the subunit. Secretion of fusion proteins: (signal peptide of Caf1)-(mature human IL-1?)-(mature Caf1), (signal peptide of Caf1)-(mature human GM-CSF)-(mature Caf1), and (signal peptide of Caf1)-(mature human IL-1ra)-(mature Caf1) that were expressed in Escherichia coli simultaneously with the periplasmic chaperone Caf1M and the usher/secretin protein Caf1A are examples of the use of the invention.