CONSTITUTIVE EXPRESSION OF A COWPEA TRYPSIN-INHIBITOR GENE, CPTI, IN TRANSGENIC RICE PLANTS CONFERS RESISTANCE TO 2 MAJOR RICE INSECT PESTS

The gene encoding a cowpea trypsin inhibitor (CpTI), which confers ins ect resistance in trangenic tobacco, was introduced into rice. Express ion of the CpTi gene driven by the constitutively active promoter of t he rice actin 1 gene (Act1) leads to high-level accumulation oi. the C pTI protein in transgenic rice plants. Protein extracts from transgeni c rice plants exhibit a strong inhibitory activity against bovine tryp sin, suggesting that the proteinase inhibitor produced in transgenic r ice is functionally active. Small-scale field tests showed that the tr ansgenic rice plants expressing the CpTi gene had significantly increa sed resistance to two species of rice stem borers, which are major ric e insect pests. Our results suggest that the cowpea trypsin inhibitor may be useful for the control of rice insect pests.