Topic 1: Regulation of plant metabolism at transcriptional and post-translational level
Metabolic engineering is the main application of synthetic biology in plant science and agriculture. Provitamin A carotenoid bioengineering in crops is one focus of such research because vitamin A is essnetial for human health but many staple crops are lacking provitamin A. Traditionally, metabolic engineering of provitamin A carotenoids focuses on the transgene of multiple enzymes into crops, which requires complicated design of multiple gene stacking and multiple efforts to reduce co-suppression. Instead, the bioengineering of the regulators, e.g. transcription factors, is an effective way to engineer a metabolic pathway, which has been well-demonstrated in anthocyanin engineering. However, lacking the understanding of the transcription factors is the major limitation.
My previous study has revealed that a conserved interaction between Golden-like transcription factors (GLKs) and G-box Binding Factors (GBFs) is critical to regulate carotenoid biosynthesis. In future, the in-silico analysis of co-expression transcription factors, molecular cloning, and high throughput in vivo interaction screening will be used to identify other transcription factors carotenoid metabolism for the future metabolic engineering in crops.
Trans-activation assay system (left figure): a, Design of the dual reporter construct. b, Imaging of bioluminescence to show the trans-activation activity. After co-transformation of pDual reporter construct and effector constructs by Agrobacteria-mediated transient expression in Nicotiana benthamiana leaves.
Post-translational regulation is critical to affect enzyme activity and protein steady level. With the advancement of protein structure determination, in silico docking, and protein-protein interaction identification, the enzyme complexes of carotenoid biosynthetic pathway and proteolysis regulators will be identified. (Right: High-accuracy enzyme structures predicted by AlphaFold)
Topic 2: Synthetic biology methods to produce products with high nutritional, or pharmaceutical values
Plants (including algae of course!) can not only provide foods, but are also green factories to produce products with high nutritional, pharmaceutical, or economical values. For example, plants have shown the potential as the host organism for rapid and large scale vaccine production, which is highly demanded during pandemic; Algae are ideal green factories to produce biofuels because of their high capacity to capture carbon. It is promising to convert those captured carbon into high value products toward Net-zero emission goal using photosynthetic organisms as synthetic chassis. One target of Sun lab is to developing efficient delivery vectors and using these green factories (plants, microalgae) as the synthetic platforms for the production of bioactive compounds with high nutritional or pharmaceutical values.