부산대학교 도서관

The maize proteinase inhibitor (mpi) gene was introduced into two elitejaponicarice varieties. Both constitutive expression of thempigene driven by the maize ubiquitin 1 promoter and wound-inducible expression of thempigene driven by its own promoter resulted in the accumulation of MPI protein in the transgenic plants. No effect on plant phenotype was observed inmpi-expressing lines. The stability of transgene expression through successive generations ofmpirice lines (up to the T4 generation) and the production of functional MPI protein were confirmed. Expression of thempigene in rice enhanced resistance to the striped stem borer (Chilo suppressalis), one of the most important pests of rice. In addition, transgenicmpiplants were evaluated in terms of their effects on the growth ofC. suppressalislarvae and the insect digestive proteolytic system. An important dose-dependent reduction of larval weight ofC. suppressalislarvae fed onmpirice, compared with larvae fed on untransformed rice plants, was observed. Analysis of the digestive proteolytic activity from the gut ofC. suppressalisdemonstrated that larvae adapted tompitransgene expression by increasing the complement of digestive proteolytic activity: the serine and cysteine endoproteinases as well as the exopeptidases leucine aminopeptidase and carboxypeptidases A and B. However, the induction of such proteolytic activity did not prevent the deleterious effects of MPI on larval growth. The introduction of thempigene into rice plants can thus be considered as a promising strategy to protect rice plants against striped stem borer. [ABSTRACT FROM AUTHOR]