Abstract: This invention provides a bacterial system and assay for detecting and quantifying activity of bacterial growth regulator, FtsH. The bacteria include three expression cassettes. An FtsH expression cassette comprises a first promoter operatively linked to a nucleotide sequence encoding FtsH. A transcriptional regulator expression cassette comprises a second promoter operatively linked to a nucleotide sequence encoding a transcriptional regulator which regulates the activity of a third promoter, wherein the transcriptional regulator is a substrate of FtsH. A reporter expression cassette comprises the third promoter operatively linked to a reporter gene. The activity of FtsH can be read out as a positive expression of the reporter gene. The invention also provides an assay for compounds that modulate the expression of FtsH. The assay involves contacting the recombinant bacterial cell with the agent, and determining whether the agent modulates the expression of the reporter gene.

Abstract: A novel thiol protease inhibitor peptide is isolated from Diabrotica virgifera designated virgiferin. The DNA encoding virgiferin and modified virgiferin peptides are claimed. These sequences maybe cloned into vectors and used to transform plants conferring reduced susceptibility to damage by plant pests that have thiol proteases as digestive enzymes including insects and nematodes and particularly Coleopteran insects.