Authors:

Anna Alden Fisher

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About Paper:

Terpenoids are among the largest and most functionally diverse classes of plant secondary metabolites, contributing to key fruit and vegetable traits, including pigmentation, flavor, aroma, and nutritional value. Their biosynthesis relies on the mevalonic acid (MVA) pathway and the methylerythritol phosphate (MEP) pathway, which exchange intermediates via the isopentenyl diphosphate (IPP) transporter. Using Solanum lycopersicum as a model system, we aimed to a) enhance terpenoid production by targeted manipulation of the MVA pathway and b) address gaps in the current understanding of terpenoid metabolic flux. Previous stable isotope labeling experiments confirmed metabolic cross- talk between the two pathways, with each pathway contributing 15-30% to the flux of the other. Terpenoid biosynthesis is developmentally regulated, and the expression of a gene encoding the IPP transporter also increased during fruit ripening. Transient transformation of mature green tomato fruits with Agrobacterium tumefaciens overexpressing key MVA pathway enzymes (e.g. HMGR1 coupled with PMK; IPK) with or without the IPP transporter led to significant changes in downstream metabolites from both pathways. Metabolomic analysis revealed statistically significant increases in limonene, carotenoids, ubiquinone, and sterols relative to empty vector (EV) fruits overexpressing IPP transporter. These results suggest that simultaneous overexpression of key MVA enzymes and the IPP transporter reshapes precursor availability and redirects metabolic flux toward terpenoid biosynthesis. Overall, our findings demonstrate that combinatorial pathway engineering can effectively modulate flux through both the MVA and MEP pathways, offering a promising strategy to enhance terpenoid biosynthesis in crops. Keywords: Terpenoid; MVA Pathway; Isopentenyl Diphosphate; Cross-Talk; Metabolomics † Presenting Undergrad Author; ‡ Contributing Undergrad Author; * Undergrad Acknowledgment

Source:

Purdue University / 2025

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Co-authors:

Anna Alden Fisher