Ethylene regulation of carotenoid accumulation and carotenogenic gene expression in colour-contrasted apricot varieties (Prunus armeniaca)

• Published in: Journal of experimental botany 2005-07, Vol.56 (417), p.1877-1886
• Main Authors: Marty, I, Bureau, S, Sarkissian, G, Gouble, B, Audergon, J. M, Albagnac, G
• Format: Article
• Language: English
• Subjects: 1-MCP; Apricot; apricots; beta-carotene; biochemical pathways; Biological and medical sciences; Biosynthesis; Botanics; carotenoid; Carotenoids; Carotenoids - biosynthesis; Cell physiology; Color; Complementary DNA; cultivars; Cyclopropanes - pharmacology; ethylene; Ethylene production; Ethylenes - metabolism; Ethylenes - pharmacology; fruit; Fruit - metabolism; fruit crops; Fruits; Fundamental and applied biological sciences. Psychology; Gene expression; Gene expression regulation; Gene Expression Regulation, Plant - drug effects; Gene Expression Regulation, Plant - physiology; Genes; Life Sciences; Molecular and cellular biology; phytoene; phytofluene; Plant Growth Regulators - metabolism; Plant Growth Regulators - pharmacology; Plant Growth Regulators - physiology; plant proteins; Polymerase chain reaction; Prunus; Prunus - drug effects; Prunus - metabolism; Prunus armeniaca; Research Papers; Ripening; ripening-related genes; Signal transduction; Vegetal Biology
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/eri177

In order to elucidate the regulation mechanisms of carotenoid biosynthesis in apricot fruit (Prunus armeniaca), carotenoid content and carotenogenic gene expression were analysed as a function of ethylene production in two colour-contrasted apricot varieties. Fruits from Goldrich (GO) were orange, while Moniqui (MO) fruits were white. Biochemical analysis showed that GO accumulated precursors of the uncoloured carotenoids, phytoene and phytofluene, and the coloured carotenoid, β-carotene, while Moniqui (MO) fruits only accumulated phytoene and phytofluene but no β-carotene. Physiological analysis showed that ethylene production was clearly weaker in GO than in MO. Carotenogenic gene expression (Psy-1, Pds, and Zds) and carotenoid accumulation were measured with respect to ethylene production which is initiated in mature green fruits at the onset of the climacteric stage or following exo-ethylene or ethylene-receptor inhibitor (1-MCP) treatments. Results showed (i) systematically stronger expression of carotenogenic genes in white than in orange fruits, even for the Zds gene involved in β-carotene synthesis that is undetectable in MO fruits, (ii) ethylene-induction of Psy-1 and Pds gene expression and the corresponding product accumulation, (iii) Zds gene expression and β-carotene production independent of ethylene. The different results obtained at physiological, biochemical, and molecular levels revealed the complex regulation of carotenoid biosynthesis in apricots and led to suggestions regarding some possible ways to regulate it.