Abstract: 【OBJECTIVE】Bt corn is one of the top three large-scale commercialized transgenic pest resistance crops around the world. It is increasingly clear that the complementary durable pest control approaches, which combine the endogenous defense of the crop and the foreign genes introduction, are the promising alternative strategies for the target pest resistance management and the next generation of insect-resistant transgentic crops.【METHOD】In the present study, we tested the inducible effects of exogenous jasmonic acid (JA) on direct defense chemicals content, Bt protein concentration and related genes expression in the leaves of Bt corn cultivar 34B24 and Non-Bt cultivar 34B23 by chemical analysis, ELISA and RT-PCR.【RESULTS】The results shown that the expression of LOX,PR-2a,MPI and PR-1 genes in the treated leaf (first leaf ) was promoted by exogenous JA both in 34B24 and 34B23. As compared with the control, the concentration of DIMBOA in the treated leaf was significantly increased by 63% and 18% for 34B24 and 34B23 respectably. The total phenolic acid was also increased by 24% and 12% for 34B24 and 34B23 either. The Bt protein content of 34B24 in the treated leaf was increased by 13%, but decreased by 23% in the second leaf. The induced response of 34B24 is in a systemic way and much stronger than that of 34B23.【CONCLUSION】Those findings indicated that there is a synergistic interactions between Bt gene and jasmonic acid mediate induced defense in Bt corn.

Key words: Bt corn, jasmonic acid, direct defense chemicals, defense genes