Genetic Stability Analysis And Agronomic Traits Observation Of Insect-resistant Transgenic Maize Harboring Bt Cry1Ah Gene

Bt cry1 Ah gene has been transferred into inbred line Zong31 via Agrobacterium-mediated transformation in our previous work. A high insect-resistant transgenic event was screened from transgenic plants, which was named HGK60. We analyzed the genetic stability of HGK60 on T4 and T5 generations in genomic, transcriptional, and translational level. The results of PCR and Southern Blot analysis confirmed that the foreign cry1 Ah gene was integrated into the genome of maize and inherited stably to next generation. In HGK60 event, there were two copies of cry1 Ah gene but one insertion site inserting the Chromosome 1 of host genome, and the flanking sequence of insertion fragment was also acquired with tail-RCR analysis. RT-PCR, Western Blot, ELISA, and Immune Detection Strips analysis were used to confirm that the Cry1 Ah protein could be effectively expressed in the roots, stems, leaves,tassel, ear, and other tissues of the transgenic maize.We evaluated the transgenic event's insect resistance to Asian corn boner(Ostrinia furnacalis), Cotton ballworm(Mythimna separate(Walker)) and Oriental armyworm(Helicoverpa armigera Hubne) through laboratory and field bioassay. The results indicated that no Asian corn boner feeding on HGK60 leaves could survive. HGK60 had a toxic effect on neonate of Cotton ballworm, and different tissues of it had different insecticidal effects.Compared to the non-transgenic maize, the body-weight of armyworm on HGK60 leaves was significantly inhibited after a week of feeding. The results of field bioassay showed that HGK60 had high resistance to O.furnacalis and H.armigera, while the efficacy to M.separate was Resistant(R) level.We obtained the desirable progeny through five generation with Zheng58 and analyzed the agronomic traits. The results indicated that it had no significant difference with Zheng58 in the plant height, ear length, ear position,and ear width between HGK60 and Zheng58. However, Thousand Kernels Weight(TKW) and yield per plant of HGK60 were significantly higher than Zheng58 when artificial simulation pest outbreaks, and the growth of Zheng58 were refrained.The result showed that the transgenic Bt corn HGK60 was the candidate materials for further insect-resistant maize breeding.