Design a transgenic maize plant that expresses the *Bacillus thuringiensis* (Bt) Cry1Ab protein to confer resistance against the European corn borer. Discuss (i) choice of vector and promoter, (ii) method of gene insertion, (iii) selectable marker, (iv) regeneration protocol for obtaining transgenic plants, and (v) key biosafety considerations before commercial release.

Step-by-step solution

1. Select a binary vector that can be mobilised by *Agrobacterium* and carries a plant‐specific promoter; the maize ubiquitin promoter ensures high constitutive expression of *cry1Ab*.
2. Clone the *cry1Ab* coding sequence downstream of the promoter and insert it into the binary vector using restriction enzymes or Gibson assembly.
3. Include a selectable marker gene such as hpt that confers hygromycin resistance to allow screening of transformants.
4. Co‑cultivate maize leaf scutellum segments with *Agrobacterium* carrying the construct, then transfer the tissues to selective medium containing hygromycin and suitable plant hormones to induce callus formation. After callus proliferation, regenerate shoots and roots on regeneration media. Finally, obtain whole plants by rooting the shoots and acclimatise them in the greenhouse.
5. Screen regenerated plants for transgene integration by PCR and for Cry1Ab protein expression by ELISA or western blot.
6. Before commercial release, evaluate environmental impact, gene flow, non‑target organism effects, and comply with national biosafety regulations. Conduct confined field trials to demonstrate efficacy and safety.
7. Ensure documentation and risk assessment are submitted to the relevant regulatory authority.

Concept tested: Transgenic crop development

Published 24 September 2026 · How this solution was prepared and checked