Comparing the Effect of Two Promoters on Cassava Somatic Embryo at Transient GUS Assay Level

Abstract

35S promoter from the Cauliflower Mosaic Virus (pCaMV) is a constitutive promoter commonly used in plant genetic transformation while Cassava Mosaic Virus (pCsVMV) is another promoter which is underutilized. The combination of the two promoters was used to form (pOYE153). The method adopted includes the insertion of a β–glucuronidase reporter gene (UidA) into a promoter cassette comprising the CsVMV promoter. The second construct (pCAMBIA2310) had (pCaMV) used for the selectable marker and gene of interest. This construct was mobilized into Agrobacterium tumefaciens strain LBA4404 and then tested for expression of the UidA gene in transient assays in cassava somatic embryos. After co-cultivation of these Agrobacterium with the plant tissues, histochemical β–glucuronidase (GUS) assays were performed to determine the level of UidA gene expression in transient assays. The results showed that the pCsVMV was able to drive high gene expression of β–glucuronidase reporter gene (UidA) in the transient assays in cassava somatic embryo. Expression of the gene also increases with the increase in the day of co-cultivation and likewise expression of the gene was higher for the sample in the light than the dark.