The Research:
Previously, DEEP GREEN PANICLE1 (DGP1) family members act as transcriptional inhibitors to GOLDEN2-LIKE1/2 (GLK1/2) mediated photosynthesis in rice (Oryza sativa L.). Herein, the TIGR01589 domain of DGP1 targets metabolic enzymes for nuclear translocation, involving glycolysis (GAPC1/2/3 and PK1/4) and mitochondrial TCA cycle (PDC1, CS, SCSb, FH and MDH12.1). Moreover, it intervenes in photorespiratory pathway by altering the composition of glycine decarboxylase complex (GDC) in mitochondrion. Consequently, DGP1-targeting system in rice mediates a transition between primary and secondary metabolisms.
The category of 'leafy vegetables' comprises a wide range of varieties. Researchers report an innovative strategy to engineer pak choi (Brassica chinensis L.) through expression of chimeric protein ST containing conservative TIGR01589 domain coupled with a chloroplast-localization signal. The GLK1-promoter-driven ST expression in pak choi seedlings specifically relocates glycolytic rate-limiting enzymes (GAPC and PK) into chloroplast, without significant impacts on GLK-mediated photosynthesis and GDC-mediated photorespiration. This strategy redirects substrate flow of central glycolysis toward flavonoids biosynthesis and simultaneously accumulates photosynthate-derived sugars in pak choi leaves.
In summary, rational design of targeted protein relocalization could therefore inspire approaches enabling bespoke properties for flavor improvement in leafy vegetables.
Key Findings:
1, The DGP1-targeting system in rice mediates a transition between primary and secondary metabolisms.
2, The artificial ST-targeting system in pak choi seedlings specifically redirects glycolysis substrate flow toward flavonoids biosynthesis and simultaneously accumulates photosynthate-derived sugars.
3, This breakthrough opens new avenues for creating other leafy vegetables with intensified, sweet flavors.
Impact and Future Directions:
This research not only addresses the long-standing issue of flavor loss in modern vegetable varieties but also provides a blueprint for sustainable flavor improvement through metabolic engineering by the ST system. Their findings have immediate applications in agriculture, food industry, and consumer health, offering the potential to revitalize the sensory appeal of vegetables and encourage greater consumption.
