High level resistance to phytopathogenic fungi and oomycetes conferred by the use of a novel anti-microbial peptide

fungi and oomycete-borne plant disease constitute the largest limiting factor for crop productivity and yields both in cuba and worldwide. vast amounts of fungicidal chemicals have to be spent every year for their control, despite considerable environmental damage and the risk such chemicals pose for human health. searching for biotechnological disease control alternatives is, therefore, a priority of current research on this subject. plant defensins are small cysteine-rich peptides forming part of the defense mechanisms of plants that inhibit the growth of a wide range of phytopathogenic microorganisms. the present work describes a new cdna coding for a defensin, isolated by looking at genes induced by the inoculation of nicotiana megalosiphon with peronospora hyoscyami f. sp. tabacina, the causative pathogen of tobacco blue mould. nmdef02, the isolated gene, was expressed in the yeast pichia pastoris, and the purified recombinant protein exhibited a strong anti-microbial activity to major fungal and oomycetal plant pathogens. in addition, the constitutive expression of the nmdef02 gene in transgenic tobacco and potato plants increased their resistance to economically important diseases.