Blooming aroma secrets: Metabolite-gene correlations boost terpenoid accumulation in Kushui rose petals

As a food-and-medicinal homology plant, Kushui rose ( Rosa sertata × Rosa rugosa Yu. et Ku.) captivates humans with its distinctive aroma and health benefits. Volatile terpenoids are not only the characteristic aroma components, influencing the fragrance type of rose essential oil, but also the functional components of rose products, and their accumulation in raw materials will affect the quality of rose products. This study investigated the volatile terpenoid profiles and gene expression patterns of the petals of the Kushui rose at three blooming stages (bud, half-bloom and full-bloom) using integrated metabolomic and transcriptomic analyses. Soluble sugars and organic acids were detected using high-performance liquid chromatography, while key genes involved in terpenoids synthesis were investigated using Ribonucleic acid (RNA) sequencing and real-time quantitative polymerase chain reaction validation. The results indicated that citral is the predominant volatile organic compound in Kushui rose, monoterpenes and sesquiterpenes peaked at half-bloom stage. Citral, citronellol, and geraniol exhibited strong positive correlations with D-(+)-glucose, D-fructose, sucrose, and succinic acid. The key genes identified were RsDXS3 , RsHDS4 , and RsHDR7 , which exhibited positive correlations with geraniol, citral, citronellol, β -myrcene, and linalool. These findings provide a theoretical basis for enhancing the quality of Kushui rose and its value as a food additive.