Cloning and characterization of an Orange gene that increases carotenoid accumulation and salt stress tolerance in transgenic sweetpotato cultures

Kim, Sun Ha; Ahn, Young Ock; Ahn, Mi‐Jeong; Jeong, Jae Cheol; Lee, Haeng‐Soon; Kwak, Sang‐Soo

doi:10.1016/j.plaphy.2013.06.011

Cited by 125 publications

(122 citation statements)

References 29 publications

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“…The transcript levels of PSY along with other carotenogenesis genes were not dramatically affected by the overexpression of either AtOR or AtOR His , as shown in the other studies (Li et al, 2001;Lopez et al, 2008;Kim et al, 2013). OR was recently discovered to serve as a major posttranscriptional regulator of PSY protein level and activity , providing an explanation for a wild-type OR-mediated carotenoid biosynthesis.…”

Section: Dual Function Of Atorsupporting

confidence: 56%

“…Overexpression of a sweet potato (Ipomoea batatas) OR gene produces light-yellow calli and increases carotenoid content in the transgenic sweet potato roots (Kim et al, 2013;Park et al, 2015). Similarly, expression of AtOR produces a clear color difference with approximately 2-fold increased carotenoid levels in the AtOR ZmPSY transgenic rice calli in comparison with the ZmPSYonly transgenic lines (Bai et al, 2014).…”

Section: Both Atormentioning

confidence: 99%

See 1 more Smart Citation

A Single Amino Acid Substitution in an ORANGE Protein Promotes Carotenoid Overaccumulation in Arabidopsis

et al. 2015

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Section: Dual Function Of Atorsupporting

confidence: 56%

Section: Both Atormentioning

confidence: 99%

A Single Amino Acid Substitution in an ORANGE Protein Promotes Carotenoid Overaccumulation in Arabidopsis

et al. 2015

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“…However, previous studies have shown that the overexpression of CmOr-His or AtOr-His induces high accumulation of b-carotene, together with significant amounts of lutein, in nongreen tissue (calli) of Arabidopsis (Tzuri et al, 2015;Yuan et al, 2015a). Lutein also was amassed in potato tubers overexpressing BoOr and in sweet potato calli overexpressing engineered IbOr (Kim et al, 2013). These results suggest that the inhibition of carotenoid metabolism flux by OR also could affect lutein fate and is not limited to b-carotene.…”

Section: Inhibition Of B-carotene Turnovermentioning

confidence: 76%

Distinct Mechanisms of the ORANGE Protein in Controlling Carotenoid Flux

Chayut

Yuan

Ohali³

et al. 2016

Plant Physiol.

113

109

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b-Carotene adds nutritious value and determines the color of many fruits, including melon (Cucumis melo). In melon mesocarp, b-carotene accumulation is governed by the Orange gene (CmOr) golden single-nucleotide polymorphism (SNP) through a yet to be discovered mechanism. In Arabidopsis (Arabidopsis thaliana), OR increases carotenoid levels by posttranscriptionally regulating phytoene synthase (PSY). Here, we identified a CmOr nonsense mutation (Cmor-lowb) that lowered fruit b-carotene levels with impaired chromoplast biogenesis. Cmor-lowb exerted a minimal effect on PSY transcripts but dramatically decreased PSY protein levels and enzymatic activity, leading to reduced carotenoid metabolic flux and accumulation. However, the golden SNP was discovered to not affect PSY protein levels and carotenoid metabolic flux in melon fruit, as shown by carotenoid and immunoblot analyses of selected melon genotypes and by using chemical pathway inhibitors. The high b-carotene accumulation in golden SNP melons was found to be due to a reduced further metabolism of b-carotene. This was revealed by genetic studies with double mutants including carotenoid isomerase (yofi), a carotenoid-isomerase nonsense mutant, which arrests the turnover of prolycopene. The yofi F2 segregants accumulated prolycopene independently of the golden SNP. Moreover, Cmor-lowb was found to inhibit chromoplast formation and chloroplast disintegration in fruits from 30 d after anthesis until ripening, suggesting that CmOr regulates the chloroplast-to-chromoplast transition. Taken together, our results demonstrate that CmOr is required to achieve PSY protein levels to maintain carotenoid biosynthesis metabolic flux but that the mechanism of the CmOr golden SNP involves an inhibited metabolism downstream of b-carotene to dramatically affect both carotenoid content and plastid fate.b-Carotene, a C-40 isoprenoid molecule, is the major source of vitamin A in the human diet (Maiani et al., 2009). Lack of dietary vitamin A is a common cause of premature death and child blindness in developing countries. b-Carotene is abundant in diverse edible plant tissues such as pumpkin (Cucurbita pepo) fruits, sweet potato (Ipomoea batatas) tubers, carrot (Daucus carota) roots, kale (Brassica oleracea) leaves, mango (Mangifera indica), and orange-fleshed melon (Cucumis melo) fruits (Howitt and Pogson, 2006;Yuan et al., 2015b). In green tissues, two b-carotene molecules are located in each PSII reaction center to facilitate electron transfer and to provide photoprotection by quenching singlet oxygen products (Telfer, 2002). In many fruits and flowers, b-carotene serves as a yellow-orange colorant and as a precursor for aromatic molecules to attract pollinators and seed dispersers (Walter and Strack, 2011).b-Carotene is a metabolite in the carotenoid biosynthesis pathway that receives its precursors from the plastid-localized methyl-erythritol phosphate pathway. Carotenoid biosynthesis starts with the condensation of two geranylgeranyl diphosphate molecules, yielding the color...

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“…Previous studies of the Brassica oleracea OR gene mutation (BoOR MUT ) and its wild-type (WT) gene (BoOR) reveal that rather than affecting expression of carotenoid biosynthetic genes, BoOR MUT exerts its effect by triggering chromoplast differentiation, which enhances storage sink strength for carotenoid biosynthesis and accumulation (21)(22)(23). Interestingly, recent reports show that overexpression of a WT OR gene also promotes carotenoid accumulation in calli of rice (24) and sweet potato (25). However, the molecular basis for OR-mediated carotenoid increase is currently unknown.…”

mentioning

confidence: 99%

Arabidopsis OR proteins are the major posttranscriptional regulators of phytoene synthase in controlling carotenoid biosynthesis

Zhou

Welsch

Yang

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

250

270

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Carotenoids are indispensable natural pigments to plants and humans. Phytoene synthase (PSY), the rate-limiting enzyme in the carotenoid biosynthetic pathway, and ORANGE (OR), a regulator of chromoplast differentiation and enhancer of carotenoid biosynthesis, represent two key proteins that control carotenoid biosynthesis and accumulation in plants. However, little is known about the mechanisms underlying their posttranscriptional regulation. Here we report that PSY and OR family proteins [Arabidopsis thaliana OR (AtOR) and AtOR-like] physically interacted with each other in plastids. We found that alteration of OR expression in Arabidopsis exerted minimal effect on PSY transcript abundance. However, overexpression of AtOR significantly increased the amount of enzymatically active PSY, whereas an ator ator-like double mutant exhibited a dramatically reduced PSY level. The results indicate that the OR proteins serve as the major posttranscriptional regulators of PSY. The ator or ator-like single mutant had little effect on PSY protein levels, which involves a compensatory mechanism and suggests partial functional redundancy. In addition, modification of PSY expression resulted in altered AtOR protein levels, corroborating a mutual regulation of PSY and OR. Carotenoid content showed a correlated change with OR-mediated PSY level, demonstrating the function of OR in controlling carotenoid biosynthesis by regulating PSY. Our findings reveal a novel mechanism by which carotenoid biosynthesis is controlled via posttranscriptional regulation of PSY in plants.arotenoids are a group of C40 isoprenoids synthesized in chloroplasts, chromoplasts, and other plastids in plants. Carotenoids serve as components of photosynthetic machinery, precursors for phytohormones, and important contributors to fruit nutritional quality and flower color (1, 2). The carotenoid biosynthetic pathway in higher plants has been well defined. However, identification of the regulatory mechanisms underlying carotenoid biosynthesis remains a challenge.Phytoene synthase (PSY) catalyzes the first committed step in carotenoid biosynthesis and controls carbon flux into the carotenoid biosynthetic pathway (1-5). Alteration of PSY expression exerts profound effects on carotenoid content (6-11). A number of factors are known to affect PSY gene expression (12)(13)(14)(15)(16)(17)(18). PSY is found to be repressed by phytochrome-interacting factors in etiolated Arabidopsis seedlings (16). PSY1 expression in tomato fruits is reported to be regulated by cis-carotenoids (14) and requires the MADS-Box transcription factor RIPENING INHIBITOR (18). Recently, it was discovered that PSY protein levels in carrot roots are modulated by a negative feedback emerging from carotenoids (19). The crucial role of PSY in carotenogenesis and the multiple factors affecting its expression suggest a complex regulatory system involved in controlling PSY. However, the factors involved in posttranscriptional regulation of PSY within plastids remain a mystery. No proteins have been re...

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Cloning and characterization of an Orange gene that increases carotenoid accumulation and salt stress tolerance in transgenic sweetpotato cultures

Cited by 125 publications

References 29 publications

A Single Amino Acid Substitution in an ORANGE Protein Promotes Carotenoid Overaccumulation in Arabidopsis

A Single Amino Acid Substitution in an ORANGE Protein Promotes Carotenoid Overaccumulation in Arabidopsis

Distinct Mechanisms of the ORANGE Protein in Controlling Carotenoid Flux

Arabidopsis OR proteins are the major posttranscriptional regulators of phytoene synthase in controlling carotenoid biosynthesis

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