Revealing the aromatic sonata through terpenoid profiling and gene expression analysis of aromatic and non-aromatic coconut varieties.

Aromatic coconut represents an exceptional variety of coconut known for its distinct and delightful flavor and aroma, both of which are highly cherished by consumers. Despite its popularity, there has been a lack of systematic research on aroma components and the associated synthetic genes. In this report, we developed the metabolite profiles of terpenoids by targeted metabolomics and obtained the expression profile of genes related to terpenoid biosynthesis by RNA-seq during different coconut fruit developmental stages. Totally, we separated 26 different terpenoids in aromatic coconut pulp, among which, geranyl acetate and (-)-isosyngene emerged as the most abundant. The integrated analysis of metabolism and RNA-seq data showed that HMGS2, HMGS3, IPI/IDI1, HMGR1, HMGR3, and CMK2 as potentially key genes involved in the synthesis of terpenoids in aromatic coconut. To validate these findings, qRT-PCR was conducted on terpenoid-related genes. These findings lay a foundation for understanding aroma formation and the molecular mechanism of terpenoids in coconut fruit.