Co-silencing of Thebaine 6-O-demethylase and Codeine O-demethylase in Papaver somniferum L., Using Virus-Induced Gene Silencing

Papaver somniferum remains the sole commercial source for narcotic and variety of semisynthetic drugs. Thebaine 6-O-demethylase (T6ODM) and codeine O-demethylase (CODM) genes are related the dioxygenase family that occur at the end of biosynthesis of these alkaloids in this plant. For silencing of CODM and T6ODM genes in Papaver somniferum, a TRV2-based construct containing a conserved sequence of DIOX from the coding region of T6ODM and CODM was designed for simultaneously silencing of two mentioned genes. Emerging first leaves of 2 to 3-week-old seedling were infiltrated with Agrobacterium tumefaciens harboring silencing construct, or the empty vector (TRV2) as a control. Analysis of gene expression at the transcript level by real-time quantitative PCR (polymerase chain reaction) technique showed 86 and 87 percent reduction in gene expression of CODM and T6ODM compared with control plants, respectively. This study demonstrated the efficiency of this method for knockdown the transcript levels of specific BIA biosynthetic genes.