The Role of Carotenogenic Metabolic Flux in Carotenoid Accumulation and Chromoplast Differentiation: Lessons From the Melon Fruit

Ari Feder, Noam Chayut, Amit Gur, Zohar Freiman, Galil Tzuri, Ayala Meir, Uzi Saar, Shachar Ohali, Fabian Baumkoler, Amit Gal-On, Yula Shnaider, Dalia Wolf, Nurit Katzir, Ari Schaffer, Joseph Burger, Li Li, Yaakov Tadmor

Research output: Contribution to journalReview articlepeer-review


Carotenoids have various roles in plant physiology. Plant carotenoids are synthesized in plastids and are highly abundant in the chromoplasts of ripening fleshy fruits. Considerable research efforts have been devoted to elucidating mechanisms that regulate carotenoid biosynthesis, yet, little is known about the mechanism that triggers storage capacity, mainly through chromoplast differentiation. The Orange gene (OR) product stabilizes phytoene synthase protein (PSY) and triggers chromoplast differentiation. OR underlies carotenoid accumulation in orange cauliflower and melon. The OR’s ‘golden SNP’, found in melon, alters the highly evolutionary conserved Arginine108 to Histidine and controls β-carotene accumulation in melon fruit, in a mechanism yet to be elucidated. We have recently shown that similar carotenogenic metabolic flux is active in non-orange and orange melon fruit. This flux probably leads to carotenoid turnover but known carotenoid turnover products are not detected in non-orange fruit. Arrest of this metabolic flux, using chemical inhibitors or mutations, induces carotenoid accumulation and biogenesis of chromoplasts, regardless of the allelic state of OR. We suggest that the ‘golden SNP’ induces β-carotene accumulation probably by negatively affecting the capacity to synthesize downstream compounds. The accumulation of carotenoids induces chromoplast biogenesis through a metabolite-induced mechanism. Carotenogenic turnover flux can occur in non-photosynthetic tissues, which do not accumulate carotenoids. Arrest of this flux by the ‘golden SNP’ or other flux-arrest mutations is a potential tool for the biofortification of agricultural products with carotenoids.

Original languageEnglish
Article number1250
JournalFrontiers in Plant Science
StatePublished - 30 Oct 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
© Copyright © 2019 Feder, Chayut, Gur, Freiman, Tzuri, Meir, Saar, Ohali, Baumkoler, Gal-On, Shnaider, Wolf, Katzir, Schaffer, Burger, Li and Tadmor.


  • OR genes
  • carotenoids accumulation
  • melon (Cucumis melo L.)
  • metabolic flux
  • tomato (Solanum lycopersicum)

ASJC Scopus subject areas

  • Plant Science


Dive into the research topics of 'The Role of Carotenogenic Metabolic Flux in Carotenoid Accumulation and Chromoplast Differentiation: Lessons From the Melon Fruit'. Together they form a unique fingerprint.

Cite this