Transformation vector construction is one of the important disciplines for plant genetic transformation
studies. A series of vector consisting of hygromycin phosphotransferase (hpt) gene as the selective marker and green fluorescent protein (GFP) as the visual reporter gene, under the control of double cauliflower mosaic virus 35S (2XCaMV35S) promoter has been engineered for transformation into oil palm cells. These genes were cloned into different types of cloning and expression vectors. The cloning was carried out by using restriction enzyme digestion and ligation method. Five intermediate vectors have been created for insertion of 2XCaMV35S-HPT-35ST and 2XCaMV35S-GFP-35ST into modified pBINPLUS backbone vector for particle bombardment and Agrobacterium-based transformation protocols. All vectors were sequenced to confirm the integrity of DNA region. The vectors were later transformed into oil palm embryogenic calli using biolistic device. The viability of the vectors was initially evaluated by transient GFP fluorescence expression observed under fluorescence microscope. It was demonstrated that the 2XCaMV35S promoter was able to drive the expression of gfp as gene in oil palm calli.