ARS | Publication request: SINGLE COPY PRIMARY TRANSFORMANTS OF MAIZE OBTAINED THROUGH THE CO-INTRODUCTION OF A RECOMBINASE-EXPRESSING CONSTRUCT

Submitted to: Plant Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 1, 2001
Publication Date: July 1, 2001

Interpretive Summary: This work demonstrates that single copy transgenic maize plants can be obtained at a high frequency with the co-transformation of a recombinase gene that deletes extra copies of the integration DNA. Unlike the previous strategy developed in wheat, where multiple transgene copies were deleted away in the F1 and F2 generations, this work introduces the recombinase during the initial transformation process. Obtaining single copy transformants right way saves time and does not require genetic crosses.

Technical Abstract: We describe a variation of the method to generate single copy transgenic plants by recombinase-mediated resolution of multiple insertions. In this study, a transgene construct flanked by oppositely oriented lox sites was co-bombarded into maize cells along with a cre-expressing construct. From analysis of the regenerated plants, a high percentage of the primary transformants harbor a single copy of the introduced transgene, and among these, a majority of them also lacked the cre construct. We deduce that the expression of cre must have contributed to resolving concatemeric molecules either prior to or after DNA integration into the maize genome.