Inhibition of Colorado potato beetle larvae by a locust proteinase inhibitor peptide expressed in potato.

The cDNA for a 73-mer peptide containing two locust serine proteinase inhibitors was cloned, fused to the constitutive CaMV35S promoter and introduced into potato by Agrobacterium-mediated transformation. From 23 independent transgenic lines, three with high mRNA level and proteinase inhibitory activity were propagated in vitro and transferred to pots. The peptide from the leaves was identified by its N-terminal sequence and by K(i) values against chymotrypsin and trypsin.