Integrated volatile metabolomics and transcriptomics reveal the regulation of odor components in celery exposed to...

Light regulates the biosynthesis of plant volatile flavor metabolites, yet how supplemental blue light modulates the accumulation of volatiles in distinct celery (Apium graveolens L.) tissues and the associated molecular mechanisms remain largely unclear. In the present study, volatile metabolomics and transcriptomics approaches were employed to analyze volatile organic compounds (VOCs) and gene expression levels in celery leaves and petioles under supplementary blue light. The results revealed that supplementary blue light induced 251 and 318 differentially abundant metabolites in celery leaves and petioles, respectively. The content of 16 compounds (4 upregulated and 12 downregulated) in celery leaves significantly changed, including those with fruity, sweet, green, popcorn, and vegetable notes. Furthermore, the content of 42 compounds (31 upregulated and 11 downregulated) associated with sweet, green, fruity, cucumber, and citrus notes in celery petioles significantly changed. The combined transcriptomic and metabolomic analysis results revealed significant enrichment in phenylpropanoid metabolic pathway in celery petioles. Specifically, supplementary blue light significantly reduced CAD and CCR gene expression levels in celery, potentially reducing the contents of methyl chavicol and anethole. In conclusion, supplemental blue light significantly altered the accumulation profiles of flavor volatiles across different celery tissues, with metabolic changes concentrated in petioles and showing prominent tissue specificity. Moreover, blue light reprogrammed phenylpropanoid metabolism in petioles, driving the alterations of flavor-related volatiles. Our research clarifies the physiological basis of light-mediated flavor formation in vegetables and offers a foundation for elucidating the underlying metabolic pathways involved in plant secondary metabolism.