Integrative omics reveal mechanisms underlying floral scent biosynthesis in Lagerstroemia suprareticulata

Floral scent is a key ornamental trait in plants, and elucidating its molecular biosynthesis mechanism is important for plant breeding. Lagerstroemia suprareticulata is a unique fragrant floral germplasm resource within the genus Lagerstroemia, endemic to China. However, the molecular mechanisms underlying its distinct floral scent remain unclear. In this study, a high-quality, chromosome-level genome assembly of L. suprareticulata (337.229 Mb) was generated by integrating multiple sequencing platforms. Gas chromatography–mass spectrometry (GC–MS) was used to systematically analyze temporal variations in floral fragrance, identifying 14 key aromatic components. By integrating transcriptome data from different flowering stages with metabolic data, key gene co-expression modules were identified, and the expression of critical genes involved in the terpenoid biosynthesis pathway was characterized. Expansion of the TPS gene family likely contributes to floral scent formation in L. suprareticulata. Functional validation demonstrated that two terpene synthase genes (LsTPS27 and LsTPS67), highly expressed during flowering, could utilize GPP to synthesize linalool and FPP to synthesize trans-nerolidol. This study provides a foundation for systematically dissecting floral scent differentiation and molecular evolutionary mechanisms in the genus Lagerstroemia.