In plants the presence of multiple copies of transgenic sequences, such as the 35S promoter, sometimes induces gene silencing of the transgenes (Daxinger et al. 2008;
Velten et al. 2012; Weinhold et al. 2013). This silencing trap might be avoided when several transgenes are required by using IRES-mediated gene expression of polycistronic constructs. Furthermore, the use of the IRES system enables the synchronous expression of
multiple genes using a single promoter. Thus, the double IRES cassette system provides a useful tool for expressing multiple genes polycistronically in plants