Search bioRxiv⌕ Search

bioRxiv · 10.1101/2020.05.12.090720

Engineering and optimization of the 2-phenylethylglucosinolate production in Nicotiana benthamiana by combining biosynthetic genes from Barbarea vulgaris and Arabidopsis thaliana

Abstract

Among the glucosinolate (GLS) defense compounds characteristic of the Brassicales order, several have been shown to promote human health. This includes 2-phenylethylglucosinolate (2PE) derived from homophenylalanine (HPhe). In this study, we used transient expression in Nicotiana benthamiana to validate and characterize previously predicted key genes in the 2PE biosynthetic pathway from Barbarea vulgaris and demonstrate the feasibility of engineering 2PE production. We used genes from B. vulgaris and Arabidopsis thaliana, in which the biosynthesis of GLSs is predominantly derived from HPhe and dihomomethionine, respectively. The resulting GLS profiles partially mirrored GLS profiles in the gene donor plant, but in both cases the profiles in N. benthamiana were wider than in the native plants. We found that BvBCAT4 is a more efficient entry enzyme for biosynthesis of both HPhe and dihomomethionine and that MAM1 enzymes determine the chain-elongated profile. Co-expression of the chain elongation pathway and CYP79F6 from B. vulgaris with the remaining aliphatic GLS core pathway genes from A. thaliana, demonstrated the feasibility of engineering production of 2PE in N. benthamiana. Noticeably, the HPhe-converting enzyme BvCYP79F6 in the core GLS pathway belongs to the CYP79F subfamily, a family believed to have substrate specificity towards chain-elongated methionine derivatives. Replacing the B. vulgaris chain elongation pathway with a chimeric pathway consisting of BvBCAT4, BvMAM1, AtIPMI and AtIPMDH1 resulted in an additional 2-fold increase in 2PE production, demonstrating that chimeric pathway with genes from different species can increase flux and boost production in an engineered pathway. Our study provides a novel approach to produce the important HPhe and 2PE in a heterologous host. Chimeric engineering of a complex biosynthetic pathway enabled detailed understanding of catalytic properties of individual enzymes - a prerequisite for understanding biochemical evolution - and with biotechnological and plant breeding potentials of new-to-nature gene combinations.Competing Interest StatementThe authors have declared no competing interest.AbbreviationsGLSglucosinolate;2PE2-phenylethylglucosinolate;HPhehomophenylalanine;HMhomomethionine;DHMdihomomethionine;THMtrihomomethionine;HLhomoleucine;DHLdihomoleucine;PEITC2-phenylethyl isothiocyanate;3MTP3-(methylthio)propylglucosinolate;3MSP3-(methylsulfinyl)propylglucosinolate;4MTB4-(methylthio)butylglucosinolate;4MSB4-(methylsulfinyl)butylglucosinolate;BGLSbenzylglucosinolateView Full Text

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Wang, C., Crocoll, C., Agerbirk, N., Halkier, B. A.. 2020-05-14. Engineering and optimization of the 2-phenylethylglucosinolate production in Nicotiana benthamiana by combining biosynthetic genes from Barbarea vulgaris and Arabidopsis thaliana. https://doi.org/10.1101/2020.05.12.090720

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Antibody design across observed and forecasted antigenic evolution

The therapeutic efficacy of antibodies is often limited by the evolution of their targets. Designing or eliciting antibodies that withstand such evolution is challenging as their binding interfaces must accommodate antigenic variation. Here, we introduce Germinal Multi, a computational framework for de novo antibody design and rescue that jointly optimizes a single paratope against multiple antigenic variants. We applied Germinal Multi to cancer and viral antigens, targeting both observed antigenic variation and prospective antibody escape. Multi-target optimization yielded antibodies that bound resistance-associated EGFR variants or that neutralized antigenically distinct historical SARS-CoV-2 variants, with recognition extending to variants withheld from the design process. Beyond acting on observed evolution, we redesigned the broadly neutralizing antibody BD55-1205 to restore neutralization of a prospective escape variant engineered with guidance from an evolutionary forecasting model, while preserving activity against the parental variant. Successful candidates were identified after screening tens of designs per campaign. Together, these results establish multi-target computational design as a strategy for generating antibody breadth across observed antigenic variation and demonstrate the potential of evolutionary forecasting to guide antibody redesign against prospective escape.

synthetic biology↗

Chromosome-level genomics and cross-species enzyme screening enable high-titer bakuchiol production in Yarrowia lipolytica

The diversity of enzymes supporting bakuchiol biosynthesis remains incompletely characterized, limiting the repertoire available for microbial pathway engineering. Here, we combined chromosome-level genomics, cross-species enzyme screening and metabolic engineering to establish high-titer bakuchiol production in Yarrowia lipolytica. We assembled a 471.76-Mb Psoralea corylifolia genome anchored to 11 pseudochromosomes, with a contig N50 of 40.33 Mb. Genome-guided screening and functional validation identified four prenyltransferases from P. corylifolia and Vigna radiata whose N-terminally truncated variants supported bakuchiol production in yeast. These results extend experimental evidence for bakuchiol-producing activity across legume prenyltransferase sequences and species. For PcPT6, corresponding to the previously reported PcPT07, removing 40 N-terminal amino acids increased bakuchiol production by 53% relative to the full-length enzyme. We reconstructed bakuchiol biosynthesis in Y. lipolytica and reinforced aromatic precursor synthesis to increase p-coumaric acid supply. Coordinating mevalonate pathway reinforcement with increased t40PcPT6 gene dosage further improved bakuchiol production. Following fermentation optimization, titers reached 108.29 mg/L in shake flasks and 6.03 g/L in a 7.5-L fed-batch bioreactor. These findings connect an expanded set of functional prenyltransferases with coordinated pathway engineering, enabling gram-per-liter microbial bakuchiol production.

synthetic biology↗

Associative Learning and Memory Erasure in a Synthetic Multicellular System

Learning is a basic form of adaptation that organisms display from neural systems to single cells. In associative learning, the pairing of two stimuli lets one of them evoke the response to the other. Engineering this behavior in a living cell is difficult, because coincidence detection, memory, and conditional readout must be wired into a single regulatory network. Here we build a consortium of five E. coli strains that distributes the operations of associative learning and communicates through one diffusible quorum-sensing signal. The same signal acts as the memory trace. One strain detects the coincidence of the two inputs, a second maintains the memory through positive feedback in the shared medium, a third reads it out on the conditioned stimulus, a fourth reports the unconditioned response, and a fifth erases the memory on command. We show experimentally that the assembled consortium learns the association, since a stimulus that is silent before training evokes a strong response after pairing. Memory is retained through a medium exchange in which both stimuli are removed, and then the conditioned stimulus alone evokes the response. The reporter is not produced without its input. An erase command returns the response to the background. A population model of the consortium accounts for the sequence of responses and gives design rules for writing, retention, and erasure, and a trade-off in storing memory in a shared extracellular signal. Distributing the operations over strains makes each of them separately tunable and testable and provides a route to microbial communities that learn from their history.

synthetic biology↗