This invention provides: 1) methods for the identification of broad
spectrum holins with a high level of nonenzymatic activity in membranes;
2) conditions required for maintaining and increasing the anti-microbial
and anti-pest efficacy of holins in gene fusions; 3) a method for
effective targeting of holins expressed in plants through use of leader
peptide to direct the holin protein in the plant apoplast and xylem; 4)
methods for the control of bacterial and fungal diseases of plants and
control of insect and nematode pests that attack plants by expression of
gene fusion involving holins, C-terminal additions and leader peptides,
and optionally, endolysis; 5) methods for increasing the shelf of cut
flowers, and 6) transgenic plants useful for the production of novel
antimicrobial proteins based upon holins.