Transgene and its Expression in Transgenic Plants: A Review

Transgenic plants have the potential to increase crop yield and reduce pesticide use in agricultural systems. However, the benefits of transgenic technology will depend on maintaining and improving the agricultural performance of the modified plants and on the stable and predictable transmission and expression of the transgene in successive generations during seed production and commercial cultivation. Instability of transgene expression in plants is often associated with complex multicopy patterns of transgene integration at the same locus, as well as position effects due to random integration. The variation of transgene expression highly complicates phenotype analyses and the production of commercial crops with stable and predictable transgene performance. Multiple efforts are being directed toward achieving stable expression of transgenes with an expected level of expression. Various factors influence this variation of transgene expression in plants, including inconsistency of transgene copy numbers, the transgene insertion site and RNA silencing in the host plant. In this review, we discuss the different factors affecting the transgene expression in genomic level and various approaches that have been used to stabilize its expression.