Bean Yellow Dwarf Virus replicons for high‐level transgene expression in transgenic plants and cell cultures

Abstract

AbstractA novel stable transgenic plant expression system was developed using elements of the replication machinery of Bean Yellow Dwarf Virus (BeYDV). The system contains two transgenes: 1) The BeYDV replicon vector with an expression cassette flanked by cis‐acting DNA elements of BeYDV, and 2) The viral replication initiator protein (Rep) controlled by an alcohol‐inducible promoter. When Rep expression was triggered by treatment with ethanol, it induced release of the BeYDV replicon from stably integrated T‐DNA and episomal replication to high copy number. Replicon amplification resulted in substantially increased transgene mRNA levels (up to 80‐fold) and translation products (up to 10‐fold) after induction of Rep expression by ethanol treatment in tobacco NT1 cells and leaves of whole potato plants. Thus, the BeYDV stable transformant replicon system is a powerful tool for plant‐based production of recombinant proteins. © 2005 Wiley Periodicals, Inc.