轉殖馬鈴薯proteinase inhibitor II基因增強水稻抗蟲性

Abstract

In recent years , the development of genetically engineered crops , especially in Bt transgenic crops has been used to resolve the food deficiency problem in the world . Although the expression of Bt toxin in transgenic crops help in prevention of pests, the extreme toxicity and lethality of Bt against specific target organisms leads to the occurance of resistance to pests and disruption of ecological balance. In order to maintain the biodiversity in the environment , many scientists tend to modify the defense mechanism of plant itself to improve the pest ability. In this study, transgenic rice plants with potato proteinase inhibitor 2 (PIN 2) gene have been produced. Also to reduce the negative effect due to large amount of protein accumulation and bioenergy consumption, the endogenous wounding-inducible PIN 2 promoter was used. By this way, we expected the PIN 2 transgenic rice plants were able to raise the defense ability against behavior insect through the inference of the digestion and changing the chewing habit of insects. To produce PIN 2 transgenic rice plants , two different rice cultivars TNG 67 ( cv. Tainung 67 ) and TK 9 (cv. Taikeng 9 ) were used as starting materials and various PIN 2 gene constructs were delivered into rice by particle bombardment and agrobacterium transformation methods. Followed that, researchs on the field trails and storage test of pest control were conducted. Agrobacterium transformation produced T0 transgenic rices showed less negative traits in sterility and etiolation. The field bioassay for insect resistance of rice stem borer ( Chilo suppressalis ) showed that the introduction of potato PIN 2 gene could help transgenic rices to reduce 1/4 damage of tillings , and the reduction damage of tillings was negatively correlated with PIN activity ( CORR.= -0.34 ). Nevertheless, the larval body weight and size had slightly increased in this assay. This remain to be solved by future invesgation of the feeding behavior and digestion physiology of rice stem borer. On the other hand, the resistance bioassay against rice weevil (Sitophilus ozyzae ) with T4 transgenic TNG 67 seeds showed that after 3 months treatment, the transgenic brown grain could significantly reduced the expansion of rice weevil population by 1/2 to 3/4 folds. Thus PIN activity of brown grain had also shown a markedly negative correlationship with weevil generation ( CORR. = -0.66 ). In conclusion, this research demonstrates the practical usefulness of PIN 2 transgenic plants in resistance to pest and provided an opportunity for future field application and experimental study.