# Integrated Volatile Metabolome and Transcriptome Analysis Provides Insights into Floral Aroma Biosynthesis in Waterlilies (Nymphaea L.)

## TL;DR

This study explores the chemical and genetic basis of floral scent in waterlilies, identifying key genes and compounds involved in fragrance production.

## Contribution

The study integrates volatile metabolome and transcriptome data to uncover new genes and pathways involved in floral scent biosynthesis in waterlilies.

## Key findings

- 671 volatile organic compounds were identified across three developmental stages of waterlily stamens.
- 47,951 differentially expressed genes were found, with key pathways linked to terpenoid and phenylpropanoid biosynthesis.
- Five candidate genes strongly correlated with volatile compound accumulation were identified, three related to terpenoid biosynthesis.

## Abstract

Waterlily (Nymphaea L.), a globally renowned aquatic ornamental plant, is prized for its aesthetic flowers and intense floral fragrance. However, the molecular mechanisms underlying floral scent biosynthesis in waterlily remain poorly characterized, and integrated analyses of dynamic volatile emission patterns and their associated biosynthetic pathways are lacking. In this study, we combined headspace solid-phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC-MS) with transcriptome sequencing (RNA-seq) to investigate the composition, emission dynamics, and biosynthesis of volatile organic compounds (VOCs) in the stamens of Nymphaea ‘Paul Stetson’ across three developmental stages. A total of 671 VOCs, classified into 14 categories, were identified. Transcriptome analysis revealed 47,951 differentially expressed genes (DEGs). Integrative omics analysis demonstrated correlated DEGs and differentially accumulated volatiles were significantly enriched in pathways related to phenylpropanoid biosynthesis, terpenoid backbone biosynthesis, diterpenoid biosynthesis, and ubiquinone/other terpenoid-quinone biosynthesis. Five candidate functional genes exhibiting strong positive correlations with VOC accumulation levels were identified, three of which are implicated in terpenoid biosynthesis. These findings provide a theoretical foundation for elucidating aroma composition and biosynthesis in waterlily and offer novel avenues for the genetic improvement of fragrance traits for ornamental, beverage, and cosmetic applications.