# Molecular Characterization and Assessment of Insect Resistance of Transgenic Maize ZDRF-8

## TL;DR

Scientists developed a transgenic maize variety, ZDRF-8, that resists pests and tolerates glyphosate, with stable performance over multiple generations.

## Contribution

The novel contribution is the development and characterization of ZDRF-8 maize with insect resistance and glyphosate tolerance through precise transgene insertion.

## Key findings

- ZDRF-8 shows high resistance to major corn pests like Asian corn borers and cotton bollworms.
- The transgenic maize is glyphosate-tolerant at up to double the recommended dose.
- Transgene expression and pest resistance remained stable over more than 10 generations.

## Abstract

ZDRF-8 is a transgenic maize event created via Agrobacterium-mediated transformation for insect resistance and glyphosate tolerance by expressing Cry1Ab, Cry2Ab, and G10evo-epsps. A Southern blot analysis suggested that it is a single-copy T-DNA insertion event. The flanking genomic sequences of the T-DNA insertion suggested that its T-DNA was inserted at the terminal region of the long arm of chromosome 7 without interrupting any known or predicted genes. Event-specific PCRs based on the flanking sequence were able to detect this event specifically. Laboratory bioassays and field trials of multiple generations demonstrated that ZDRF-8 is highly active against major corn pests in China, including Asian corn borers (ACB, Ostrinia furnacalis), cotton bollworms (CBW, Helicoverpa armigera), and oriental armyworm (OAW, Mythimna separata), and meanwhile confers glyphosate tolerance up to two times the recommended dose. The expression of the transgenes and the efficacy of insect resistance and glyphosate tolerance were stable over more than 10 generations. ZDRF-8 has been granted with a safety certificate in China, and its commercial release is expected in the coming years.