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Jung S, Maeda HA. Debottlenecking the L-DOPA 4,5-dioxygenase step with enhanced tyrosine supply boosts betalain production in Nicotiana benthamiana. PLANT PHYSIOLOGY 2024; 195:2456-2471. [PMID: 38498597 DOI: 10.1093/plphys/kiae166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/26/2024] [Accepted: 02/26/2024] [Indexed: 03/20/2024]
Abstract
Synthetic biology provides emerging tools to produce valuable compounds in plant hosts as sustainable chemical production platforms. However, little is known about how supply and utilization of precursors is coordinated at the interface of plant primary and specialized metabolism, limiting our ability to efficiently produce high levels of target specialized metabolites in plants. L-Tyrosine is an aromatic amino acid precursor of diverse plant natural products including betalain pigments, which are used as the major natural food red colorants and more recently a visual marker for plant transformation. Here, we studied the impact of enhanced L-tyrosine supply on the production of betalain pigments by expressing arogenate dehydrogenase (TyrA) from table beet (Beta vulgaris, BvTyrAα), which has relaxed feedback inhibition by L-tyrosine. Unexpectedly, betalain levels were reduced when BvTyrAα was coexpressed with the betalain pathway genes in Nicotiana benthamiana leaves; L-tyrosine and 3,4-dihydroxy-L-phenylalanine (L-DOPA) levels were drastically elevated but not efficiently converted to betalains. An additional expression of L-DOPA 4,5-dioxygenase (DODA), but not CYP76AD1 or cyclo-DOPA 5-O-glucosyltransferase, together with BvTyrAα and the betalain pathway, drastically enhanced betalain production, indicating that DODA is a major rate-limiting step of betalain biosynthesis in this system. Learning from this initial test and further debottlenecking the DODA step maximized betalain yield to an equivalent or higher level than that in table beet. Our data suggest that balancing between enhanced supply ("push") and effective utilization ("pull") of precursor by alleviating a bottleneck step is critical in successful plant synthetic biology to produce high levels of target compounds.
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Affiliation(s)
- Soyoung Jung
- Department of Botany, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Hiroshi A Maeda
- Department of Botany, University of Wisconsin-Madison, Madison, WI 53706, USA
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Willoughby AC. CRISPR, chimerism, and chromothripsis: A technique for studying DNA repair in plants. THE PLANT CELL 2023; 35:3916-3917. [PMID: 37607104 PMCID: PMC10615198 DOI: 10.1093/plcell/koad221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 08/16/2023] [Indexed: 08/24/2023]
Affiliation(s)
- Andrew C Willoughby
- Assistant Features Editor, The Plant Cell, American Society of Plant Biologists
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27713, USA
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Chen J, Luo M, Hands P, Rolland V, Zhang J, Li Z, Outram M, Dodds P, Ayliffe M. A split GAL4 RUBY assay for visual in planta detection of protein-protein interactions. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 114:1209-1226. [PMID: 37323061 DOI: 10.1111/tpj.16234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 03/23/2023] [Accepted: 03/28/2023] [Indexed: 06/17/2023]
Abstract
Protein-protein interactions (PPIs) are a fundamental process in cellular biogenesis. Here we have developed a split GAL4 RUBY assay that enables macroscopically visual PPI detection in plant leaves in real time. Candidate interacting protein partners are fused to specific domains of the yeast GAL4 and herpes simplex virus VP16 transcription factors and transiently expressed in Nicotiana benthamina leaves by Agrobacterium infiltration. PPI, that may be either direct or indirect, results in transcriptional activation of a RUBY reporter gene leading to the production of the highly visual metabolite, betalain, in leaf tissue of living plants. Samples require no processing for in planta visual qualitative assessment, but with very simple processing steps the assay is quantitative. Its accuracy is demonstrated using a series of known interacting protein partners and mutant derivatives including transcription factors, signalling molecules and plant resistance proteins with cognate pathogen effectors. Using this assay, association between the wheat Sr27 stem rust disease resistance protein and corresponding AvrSr27 avirulence effector family produced by the rust pathogen is detected. Interaction is also observed between this resistance protein and the effector encoded by the corresponding avrSr27-3 virulence allele. However, this association appears weaker in the split GAL4 RUBY assay, which coupled with lower avrSr27-3 expression during stem rust infection, likely enables virulent races of the rust pathogen to avoid Sr27-mediated detection.
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Affiliation(s)
- Jian Chen
- CSIRO Agriculture and Food, Box 1700, Clunies Ross St, Canberra, Australia, 2601
| | - Ming Luo
- CSIRO Agriculture and Food, Box 1700, Clunies Ross St, Canberra, Australia, 2601
| | - Phillip Hands
- CSIRO Agriculture and Food, Box 1700, Clunies Ross St, Canberra, Australia, 2601
| | - Vivien Rolland
- CSIRO Agriculture and Food, Box 1700, Clunies Ross St, Canberra, Australia, 2601
| | - Jianping Zhang
- CSIRO Agriculture and Food, Box 1700, Clunies Ross St, Canberra, Australia, 2601
| | - Zhao Li
- Australian National University, Canberra, Australia, 2601
| | - Megan Outram
- CSIRO Agriculture and Food, Box 1700, Clunies Ross St, Canberra, Australia, 2601
| | - Peter Dodds
- CSIRO Agriculture and Food, Box 1700, Clunies Ross St, Canberra, Australia, 2601
| | - Michael Ayliffe
- CSIRO Agriculture and Food, Box 1700, Clunies Ross St, Canberra, Australia, 2601
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