Abstract
Salicylate 2-O-β-D-glucoside (SAG) is a plant-derived natural product with potential utility as both an anti-inflammatory and as a plant protectant compound. Heterologous biosynthesis of SAG has been established in Escherichia coli through metabolic engineering of the shikimate pathways and introduction of a heterologous biosynthetic step to allow a more directed route to the salicylate precursor. The final SAG compound resulted from the separate introduction of an Arabidopsis thaliana glucosyltransferase enzyme. In this study, a range of heterologous engineering parameters were varied (including biosynthetic pathway construction, expression plasmid, and E. coli strain) for the improvement of SAG specific production in conjunction with a system demonstrating improved plasmid stability. In addition, the glucoside moiety of SAG was systematically varied through the introduction of the heterologous oliose and olivose deoxysugar pathways. Production of analogs was observed for each newly constructed pathway, demonstrating biosynthetic diversification potential; however, production titers were reduced relative to the original SAG compound.
Highlights
Plants have dedicated metabolism for the production of salicylate and a glycosylated version, salicylate 2-O-β-D-glucoside (SAG), which is often stored intracellularly until external stress is encountered (Vlot et al, 2009; Rivas-San Vicente and Plasencia, 2011)
Leveraging the knowledge and prior studies associated with engineering the shikimate pathway of Escherichia coli (Lin et al, 2014), we generated a production host supportive of high titer levels of salicylate (>1 g/L) (Ahmadi et al, 2016)
A production comparison revealed that the BW23(DE3)/pRSQ2 strain generated the best relative Salicylate 2-O-β-D-glucoside (SAG) levels based upon volumetric and specific titer comparisons (Figures 2B,C and Supplementary Figure S5)
Summary
Plants have dedicated metabolism for the production of salicylate and a glycosylated version, salicylate 2-O-β-D-glucoside (SAG), which is often stored intracellularly until external stress is encountered (Vlot et al, 2009; Rivas-San Vicente and Plasencia, 2011). The reversion of SAG to salicylate allows the bioactivity of the latter compound to combat various biological threats to the plant system. Salicylate is a central component of aspirin and, as such, SAG has the potential to possess similar anti-inflammatory properties. These various bioactivities of SAG prompted us to explore its production through a heterologous bacterial host. This work included the introduction of an Irp salicylate synthase gene from Yersinia enterocolitica, which streamlined metabolism toward this precursor (Figure 1; Pelludat et al, 2003; Kerbarh et al, 2005). The introduction of a glucosyltransferase gene (ugt74f1) from Arabidopsis thaliana enabled conversion to the final SAG compound (Ahmadi et al, 2016)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
