From fruit to function: Squalene synthase driven triterpenoids biosynthesis in Gardenia jasminoides for food-active ingredient discovery

The medicinal and edible plant Gardenia jasminoides is attracting attention as a source of natural food-active components. Integrated GC–MS/LC-MS metabolomics revealed that G. jasminoides fruits specifically accumulate bioactive triterpenoids, including the GRAS antioxidant squalene (220 ng/mg FW) and methyl oleanonate, a compound with reported anticancer (PPARγ agonist) activity. As the central biosynthetic hub, GjSQS showed fruit-predominant expression, strongly correlating with triterpenoid abundance. Functional validation confirmed its ER localization and efficient in vitro conversion of FPP to squalene. The dual-ionization LC-MS approach revealed tissue-partitioned acidic triterpenoids that were undetectable using single ionization modes, enhancing the comprehensiveness of metabolomic profiling. These findings underscore G. jasminoides fruits as a sustainable source of food-active triterpenoids and establish GjSQS as a key metabolic engineering target. Its expression in food-grade microbial chassis offers a promising strategy to enhance the production of high-value triterpenoids for functional foods and additives. • Gardenia jasminoides fruits are a natural reservoir of food-active triterpenoids, including squalene (220 ng/mg FW, GRAS-certified), niga-ichigoside F1 (50.31 μg/g FW), glycyrrhizic acid (0.35 μg/g FW), methyl oleanonate (a compound with reported anticancer PPARγ agonist activity). • Squalene synthase (GjSQS) acted as a rate-limiting regulator, with higher expression in fruits, strongly correlating with triterpenoid contents. • GjSQS localized to the endoplasmic reticulum (ER) and efficiently catalyzed farnesyl pyrophosphate to squalene conversion, enabling targeted precursor channeling for bioactive triterpenoid synthesis. • A dual-ionization LC-MS strategy expands the detectable triterpenoid metabolome, revealing tissue-specific acidic triterpenoids previously undetectable in single-mode analysis. • GjSQS provides a validated genetic target for metabolic engineering to enhance high-value anticancer triterpenoids in food-grade yeast chassis.