DEVELOPMENT OF INSECT-RESISTANT TRANSGENIC PLANTS USING PLANT GENES -EXPRESSION OF COWPEA TRYPSIN-INHIBITOR IN TRANSGENIC TOBACCO PLANTS

Development of transgenic plants, engineered for insect resistance, ha s added a new dimension to crop improvement. The cowpea trypsin inhibi tor (CpTI) gene offers resistance against a wide range of insects, and has been used for developing insect-resistant plants. In the present study, the CpTI gene, amplified by PCR, was cloned in a plant expressi on vector under the control of the CaMV 35S promoter and the NOS termi nator, and introduced into model plant tobacco by Agrobacterium-mediat ed transformation. The presence and expression of the CpTI gene in pri mary transformants R-0 and R-1 progeny was confirmed by PCR and immuno biochemical analyses. The efficacy of the expressed CpTI protein again st Spodoptera litura was tested by feeding trial larvae under laborato ry conditions. Reduction to the extent of 50% was observed in the biom ass of S. litura larvae fed on transgenic leaves, expressing 3-5 mu g CpTI/g fresh tissue.