Expression Pattern And Ecological Adaptability Of The Bt Protein In Transgenic Rice

With Bt gene (cry1C and cry2A) of Minghui63as research objects, we detected the variation of Bt protein expression under different growth conditions to investigate the relationship of its growth conditions and growth period, and to analysis the effectors of ecological adaptability, especially seed set, which can provide a reference basis for the production and application of Bt transgenic rice.The main findings are as follows:1. The expression levels of Bt protein presented a certain trend in leaf of Bt transgenic rice TIC-19and T2A-1. It performed a increasing trend with time from the seedling stage to the tillering stage, then gradually leveled off at the tillering stage, and reached to the highest levels in the booting stage. The Bt protein expression of stem was much lower than its in leaves. The expression pattern was also quite different. Its gradually increased and stabilized from the jointing stage, and went a rapid drop during the mature period. Overall, the trend was increase first, then decrease.2. Under high or low temperature stress treatments, the Bt protein expression in vegetative tissues was normal; however, the Bt protein synthesis reduced to a certain extent, which contents was below the required level of insect resistance.3. The seed germination rate of Bt transgenic rice had no significant difference with their two parents.4. In different planting time and environmental conditions, the Bt transgenic rice TIC-19had a lower setting percentage compared with the control parents, while the T2A had no significant difference with their parents. Other agronomic traits of these two transgenic plants had no significant difference with their parents, such as grain number per spike, pollen viability and so on. At different temperature treatments of the booting stage and flowering stage, the TIC-19also had a lower setting percentage than the control parents. So we speculated that different Bt genes had different effects on the seed setting rate and the temperature adaptation. Our study showed that the expression of two Bt genes cry1C and cry2A had a more stable ecological adaptability, and the protein dynamic level of different growth stages were corresponds to the occurrence rule of rice stem borer, so these two genes were an excellent insect-resistant genes. Moreover, these two genes had no significant effect on rice agronomic traits and seed vigor. However, their products had different effects on the seed setting rate and temperature adaption, the reasons need to be further studied.