Aroma formation in single- and double-petal jasmines (Jasminum sambac) during flowering via volatile metabolome and transcriptome

Abstract

Jasminum sambac (L.) Aiton exists in single-petal (SP), double-petal (DP), and multi-petal (MP) phenotypes, which have a sweet floral scent and release aroma when the flowers open. A total of 103 volatiles were discovered from SP and DP jasmines. 16 volatiles were identified as their key odorants. Caryophyllene, geraniol, linalool, α-farnesene, β-ocimene, methyl anthranilate, methyl salicylate, benzeneacetaldehyde and hexanal may form the overall aroma of those two jasmines during flowering. High-resolution transcriptional profiles of those two jasmines at four flowering stages were generated from our recently reported chromosome-level genome assembly, from which we identified 35 differentially expressed genes (DEGs) involved in terpenoid metabolic pathways and 10 DEGs involved in the phenylpropane/benzene metabolic pathway, which may shape the characteristic aroma of those two jasmines at the molecular level. Through co-expression network analysis of key odorants, we found that bZIP8, bHLH6, MYB4, and AP2/ERF3 may contribute to the regulation of aroma volatiles in those two jasmines. These results offer an important theoretical foundation for studying the regulation of aroma formation for SP and DP jasmines.