Four Petal-Specific TPS Drive Nocturnal Terpene Scent in Jasminum sambac

Floral volatile terpenoids are known to play important roles in plant pollination biology by attracting animal pollinators, repelling antagonists, and enhancing resistance to potential microbial pathogens. The terpenoid blend emitted by a flower is usually plant-lineage specific and is primarily determined by a set of versatile terpene synthases (TPSs), which catalyze the final step of diverse terpenoid synthesis. The strongly scented flower of Jasminum sambac (L.) Aiton emits linalool and α-farnesene, which dominate the nocturnal floral VOCs, yet the corresponding TPSs have not been identified. Here, we show that four TPS enzymes are responsible for the synthesis of a mixture of volatile terpenoids in the flower, based on their highly correlated and almost exclusive expression in the petal, as well as their enzymatic characterizations in vitro and in Nicotiana benthamiana Domin. JsTPS01 (TPS-a) acts as a sesquiterpene synthase, producing τ-cadinol in yeast at levels that mirror its rhythmic expression in petals. JsTPS02 (TPS-b) carries a plastid-targeting transit peptide, localizes to chloroplasts/plastids, and converts geranyl diphosphate (GPP) to linalool with high affinity (Km = 28.2 ± 3.4 µM). JsTPS03 is a TPS-b clade member that can convert farnesyl diphosphate (FPP) to farnesol with a Km of 14.4 ± 5.9 μM in an in vitro assay using isolated yeast vehicles. JsTPS04 (TPS-e/f) exhibits dual targeting—cytosolic in protoplasts of Arabidopsis thaliana (L.) Heynh, but plastidic in J. sambac petals—and functions as a bifunctional mono-/sesqui-TPS, forming linalool from GPP (Km = 2.5 ± 0.3 µM) and trans-nerolidol from FPP (Km = 7.6 ± 0.6 µM). Transient expression in N. benthamiana leaves further confirmed its in-planta linalool production. Collectively, we identified four preferentially expressed terpene synthases that contribute to the production of linalool, τ-cadinol, trans-nerolidol, and farnesol in J. sambac.