Apocarotenoid profiling in saffron: Tissue-specific changes across growth phases.

Area of Science:

• Plant metabolomics
• Carotenoid biochemistry
• Saffron (Crocus sativus L.) biology

Background:

• Apocarotenoids (crocetin, crocins, picrocrocin) are vital saffron metabolites.
• Their synthesis in stigmas is known, but tissue redistribution and persistence are unclear.

Purpose of the Study:

• To investigate the temporal and spatial dynamics of apocarotenoids in saffron tissues throughout its life cycle.
• To understand the metabolic fate and functional roles of these compounds beyond stigma.

Main Methods:

• LC-HRMS-based metabolomic profiling was employed.
• Analysis covered multiple tissues (stigma, ovary, peduncle, corm, roots) across three developmental stages.
• PCA and heatmap analyses were used for data interpretation.

Main Results:

• Pronounced tissue-specific specialization of apocarotenoid accumulation was observed.
• Stigmas showed high trans-crocin abundance during flowering; ovaries and roots accumulated different compounds in spring.
• New corms contained glycosylated cis-crocin 3, suggesting de novo synthesis and stabilization.

Conclusions:

• Apocarotenoids are not degraded post-flowering but are redistributed and modified.
• These compounds support vegetative development, storage, and potential protective functions in underground tissues.
• Metabolite clustering revealed distinct crocin and picrocrocin pathways and isomer-specific relationships.