Evaluation of transient DsRED gene expression in oil palm embryogenic calli

Abstract Genetic modification of oil palm is being carried out to explore new avenues for improving and expanding the potential of oil palm. Multiple bottlenecks in delivering the DNA into oil palm cells and generating the transgenic oil palm required us to look into an alternative marker which could help us assess the efficiency of the transformation system, moreover at the early stage considering that oil palm is a slow growing plant. In this study, we have constructed seven transformation vectors carrying a gene encoding DsRED, each driven by a different promoter, i.e. plant constitutive promoter, oil palm constitutive promoter or oil palm tissue-specific promoter. The vectors were transformed into oil palm embryogenic calli via microprojectile bombardment and the red fluorescence signals were observed after 48 h. Based on the observation, the construct driven by the CaMV35S promoter produced the highest number of red fluorescent spots. The oil palm calli bombarded with pUbi-DsRED plasmid suffered the most number of red fluorescent spots losses from day three until day 42, as compared to other constructs. The red fluorescent signals of DsRED produced across all transformed samples appeared to be bright and very distinctive as compared to the background.