关键词: 转基因玉米, G23V-EPSPS基因, 抗草甘膦, ddPCR

Abstract: In this study, EPSPS gene deriving from Arthrobacter globiformis was optimized with maize biased codons and synthesized. The synthesized gene named as G23V was cloned into plant expression vector pBAC9200. The vector was transformed into immature embryos of maize (Zea mays) inbred lines 501 with Agrobacterium-mediated transformation method. Total 14 regenerated plants were obtained following steps of callus induction, glyphosate resistance screening and differentiation culture. PCR, RT-PCR detection showed that five transformed plants possessed G23V-EPSPS genes integration and expression on the transcriptional level. Finally, G23V-EPSPS genes insertion copy number was detected using droplet digital PCR technology. The results showed that, in the five confirmed genetically modified plants, the copy number of G23V-EPSPS gene was 0.12, 1.0, 0.9, 1.89, 0.66, respectively, ranging between 0 to 2. The study established genetic transformation system of glyphosate resistance gene in maize, which laid the foundation for EPSPS gene as selection marker in transgenosis. Besides, droplet digital PCR technology is a simple and rapid method to analyze foreign genes insertion copy number, and could replace traditional Southern Blot method in the near future.

Key words: transgenic maize, G23V-EPSPS gene, glyphosate resistance, ddPCR