Chromoplasts ultrastructure and estimated carotene content in root secondary phloem of different carrot varieties

Kim, Ji Eun; Rensing, Kim H.; Douglas, Carl J.; Cheng, Kimberly M.

doi:10.1007/s00425-009-1071-7

Cited by 83 publications

(61 citation statements)

References 39 publications

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“…From the nutritional point of view, however, much more relevant is the quantitative variation observed among genotypes producing yellow roots (ranging from 3.0 to 30.0 μg/g). Interesting studies in carrot compared roots from three cultivars: one producing white roots with negligible amounts of carotenoids crystals (CC) and two cultivars producing yellow roots with vast differences in CC [71]. In this study, the authors concluded that the difference in CC among the two cultivars producing yellow roots was not due to increased numbers of carotene-containing chromoplasts but rather greater accumulation of carotene per chromoplast.…”

Section: Inheritance Of Carotenoids Content In Cassava Rootsmentioning

confidence: 81%

Carotenoids in Cassava Roots

Ceballos¹,

Davrieux²,

Talsma³

et al. 2017

Carotenoids

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Vitamin A deficiency (VAD) is a preventable tragedy that affects millions of people, particularly in sub-Saharan Africa. A large proportion of these people rely on diets based on cassava as a source of calories. During the last two decades, significant efforts have been made to identify sources of germplasm with high pro-vitamin A carotenoids (pVAC) and then use them to develop cultivars with a nutritional goal of 15 μg g −1 of β-carotene (fresh weight basis) and good agronomic performance. The protocols for sampling roots and quantifying carotenoids have been improved. Recently, NIR predictions began to be used. Retention of carotenoids after different root processing methods has been measured. Bioavailability studies suggest high conversion rates. Genetic modification has also been achieved with mixed results. Carotenogenesis genes have been characterized and their activity in roots measured.

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Section: Inheritance Of Carotenoids Content In Cassava Rootsmentioning

confidence: 81%

Carotenoids in Cassava Roots

Ceballos¹,

Davrieux²,

Talsma³

et al. 2017

Carotenoids

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“…Reticulotubular structures made of a reticulum of tubules are abundant in saffron, bananas and Cucurbita maxima , but vesicles and globules also coexist ( Grilli-Caiola and Canini 2004 ). Some chromoplasts accumulate carotenoids as large crystals inside the lumina of thylakoid-like structures, such as in carrot roots and daffodil petals, and plastoglubuli containing small amounts of carotenoids are also present, although in small size and number ( Kim et al 2010 ). Mango fruit chromoplasts contain large and numerous globules as well as a network of tubular membranes.…”

Section: Diversity Of Chromoplast Structuresmentioning

confidence: 99%

Chromoplast Differentiation: Current Status and Perspectives

Egea¹,

Barsan²,

Bian³

et al. 2010

Plant and Cell Physiology

243

191

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Chromoplasts are carotenoid-accumulating plastids conferring color to many fl owers and fruits as well as to some tubers and roots. Chromoplast differentiation proceeds from preexisting plastids, most often chloroplasts. One of the most prominent changes is remodeling of the internal membrane system associated with the formation of carotenoidaccumulating structures. During the differentiation process the plastid genome is essentially stable and transcriptional activity is restricted. The buildup of the chromoplast for specifi c metabolic characteristics is essentially dependent upon the transcriptional activity of the nucleus. Important progress has been made in terms of mediation of the chloroplast-to-chromoplast transition with the discovery of the crucial role of the Or gene. In this article we review recent developments in the structural, biochemical and molecular aspects of chromoplast differentiation and also consider the reverse differentiation of chromoplasts into chloroplast-like structures during the regreening process occurring in some fruit. Future perspectives toward a full understanding of chromoplast differentiation include in-depth knowledge of the changes occurring in the plastidial proteome during chromoplastogenesis, elucidation of the role of hormones and the search for signals that govern the dialog between the nuclear and the chromoplastic genome. Keywords: Carotenoids synthesisAbbreviations : ABA , abscisic acid ; ARC5 , accumulation and replication of chloroplasts5 ; ARF4 , auxin response factor ; CHRC , plastoglobulin carotenoid-associated protein ; DDB1 , UV-damaged DNA-binding protein 1 ; DET1 , deetiolated 1 ; GFP , green fl uorescent protein ; MFP1 , thylakoid-associated DNA-binding protein ; ORFs , open reading frames ; PVD1 , plastid division1 ; PVD2 , plastid division 2 ; ROS , reactive oxygen species.

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“…In carrot roots, carotenoids accumulate as crystals within chromoplasts (Maass et al, 2009;Kim et al, 2010;Wang et al, 2013). In leaf chloroplasts, these pigments are mostly protein-bound, forming essential constituents of light-harvesting complexes and photosynthetic reaction centers.…”

Section: Introductionmentioning

confidence: 99%

Carotene Hydroxylase Activity Determines the Levels of Both α-Carotene and Total Carotenoids in Orange Carrots

et al. 2014

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The typically intense carotenoid accumulation in cultivated orange-rooted carrots (Daucus carota) is determined by a high protein abundance of the rate-limiting enzyme for carotenoid biosynthesis, phytoene synthase (PSY), as compared with white-rooted cultivars. However, in contrast to other carotenoid accumulating systems, orange carrots are characterized by unusually high levels of a-carotene in addition to b-carotene. We found similarly increased a-carotene levels in leaves of orange carrots compared with white-rooted cultivars. This has also been observed in the Arabidopsis thaliana lut5 mutant carrying a defective carotene hydroxylase CYP97A3 gene. In fact, overexpression of CYP97A3 in orange carrots restored leaf carotenoid patterns almost to those found in white-rooted cultivars and strongly reduced a-carotene levels in the roots. Unexpectedly, this was accompanied by a 30 to 50% reduction in total root carotenoids and correlated with reduced PSY protein levels while PSY expression was unchanged. This suggests a negative feedback emerging from carotenoid metabolites determining PSY protein levels and, thus, total carotenoid flux. Furthermore, we identified a deficient CYP97A3 allele containing a frame-shift insertion in orange carrots. Association mapping analysis using a large carrot population revealed a significant association of this polymorphism with both a-carotene content and the a-/b-carotene ratio and explained a large proportion of the observed variation in carrots.

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Chromoplasts ultrastructure and estimated carotene content in root secondary phloem of different carrot varieties

Cited by 83 publications

References 39 publications

Carotenoids in Cassava Roots

Carotenoids in Cassava Roots

Chromoplast Differentiation: Current Status and Perspectives

Carotene Hydroxylase Activity Determines the Levels of Both α-Carotene and Total Carotenoids in Orange Carrots

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