Transient gene expression in plants and its application in molecular farming and functional genomics

Transient expression is widely used as an alternative method for stable transformation of plants, especially cereals, trees and recalcitrants. In this method, multiple copies of transgene are introduced in to the plant cell and then are transcribed and translated. As introduced gene is not integrated in the genome, its expression is not affected by epigenetic factors and the location of insertion. Transient expression is a convenient method for functional analysis of genes including overexpression, silencing, gene expression networks, protein localization, promoter analysis, identification of biosynthesis pathways and so on. Additionally, this method is applied in biotechnological industries like production of recombinant proteins. Transient transformation is performed by different methods, however, many of them have overlap. So, a combination of these methods can be used for transient expression. In this review, various transient transformation techniques, their advantages and disadvantages, latest progress regarding transient expression in model and crop plants and potential and limitations regarding the application of transient expression technique in science and industry will be discussed.