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Liang MH, Xie SR, Chen HH, Jiang JG. DbMADS regulates carotenoid metabolism by repressing two carotenogenic genes in the green alga Dunaliella sp. FACHB-847. J Cell Physiol 2023; 238:1324-1335. [PMID: 37087727 DOI: 10.1002/jcp.31017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/11/2023] [Accepted: 03/14/2023] [Indexed: 04/24/2023]
Abstract
MADS transcription factors are involved in the regulation of fruit development and carotenoid metabolism in plants. However, whether and how carotenoid accumulation is regulated by algal MADS are largely unknown. In this study, we first used functional complementation to confirm the functional activity of phytoene synthase from the lutein-rich Dunaliella sp. FACHB-847 (DbPSY), the key rate-limiting enzyme in the carotenoid biosynthesis. Promoters of DbPSY and DbLcyB (lycopene β-cyclase) possessed multiple cis-acting elements such as light-, UV-B-, dehydration-, anaerobic-, and salt-responsive elements, W-box, and C-A-rich-G-box (MADS-box). Meanwhile, we isolated one nucleus-localized MADS transcription factor (DbMADS), belonging to type I MADS gene. Three carotenogenic genes, DbPSY, DbLcyB, and DbBCH (β-carotene hydroxylase) genes were upregulated at later stages, which was well correlated with the carotenoid accumulation. In contrast, DbMADS gene was highly expressed at lag phase with low carotenoid accumulation. Yeast one-hybrid assay and dual-luciferase reporter assay demonstrated that DbMADS could directly bind to the promoters of two carotenogenic genes, DbPSY and DbLcyB, and repress their transcriptions. This study suggested that DbMADS may act as a negative regulator of carotenoid biosynthesis by repressing DbPSY and DbLcyB at the lag phase, which provide new insights into the regulatory mechanisms of carotenoid metabolism in Dunaliella.
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Affiliation(s)
- Ming-Hua Liang
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Institute of Ecological Science, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Shan-Rong Xie
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Hao-Hong Chen
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Jian-Guo Jiang
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
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2
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Göttl VL, Pucker B, Wendisch VF, Henke NA. Screening of Structurally Distinct Lycopene β-Cyclases for Production of the Cyclic C40 Carotenoids β-Carotene and Astaxanthin by Corynebacterium glutamicum. J Agric Food Chem 2023; 71:7765-7776. [PMID: 37162369 DOI: 10.1021/acs.jafc.3c01492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Lycopene β-cyclase (EC 5.5.1.19) is one of the key enzymes in the biosynthesis of β-carotene and derived carotenoids. It catalyzes isomerase reactions to form β-carotene from lycopene by β-cyclization of both of its ψ-ends. Lycopene β-cyclases are widespread in nature. We systematically analyzed the phylogeny of lycopene β-cyclases from all kingdoms of life and predicted their transmembrane structures. To this end, a collection of previously characterized lycopene β-cyclase polypeptide sequences served as bait sequences to identify their closest homologues in a range of bacteria, archaea, fungi, algae, and plant species. Furthermore, a DeepTMHMM scan was applied to search for the presence of transmembrane domains. A phylogenetic tree suggests at least five distinct clades, and the DeepTMHMM scan revealed that lycopene β-cyclases are a group of structurally different proteins: membrane-bound and cytosolic enzymes. Representative lycopene β-cyclases were screened in the lycopene-overproducing Corynebacterium glutamicum strain for β-carotene and astaxanthin production. This systematic screening facilitates the identification of new enzymes for carotenoid production. Higher astaxanthin production and less reduction of total carotenoids were achieved with the cytosolic lycopene β-cyclase CrtL from Synechococcus elongatus and the membrane-bound heterodimeric lycopene β-cyclase CrtYcd from Brevibacterium linens.
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Affiliation(s)
- Vanessa L Göttl
- Genetics of Prokaryotes, Faculty of Biology and CeBiTec, Bielefeld University, 33615 Bielefeld, Germany
| | - Boas Pucker
- Institute of Plant Biology & BRICS, TU Braunschweig, 38106 Braunschweig, Germany
| | - Volker F Wendisch
- Genetics of Prokaryotes, Faculty of Biology and CeBiTec, Bielefeld University, 33615 Bielefeld, Germany
| | - Nadja A Henke
- Genetics of Prokaryotes, Faculty of Biology and CeBiTec, Bielefeld University, 33615 Bielefeld, Germany
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3
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Kössler S, Armarego-Marriott T, Tarkowská D, Turečková V, Agrawal S, Mi J, de Souza LP, Schöttler MA, Schadach A, Fröhlich A, Bock R, Al-Babili S, Ruf S, Sampathkumar A, Moreno JC. Lycopene β-cyclase expression influences plant physiology, development, and metabolism in tobacco plants. J Exp Bot 2021; 72:2544-2569. [PMID: 33484250 PMCID: PMC8006556 DOI: 10.1093/jxb/erab029] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 01/19/2021] [Indexed: 05/12/2023]
Abstract
Carotenoids are important isoprenoids produced in the plastids of photosynthetic organisms that play key roles in photoprotection and antioxidative processes. β-Carotene is generated from lycopene by lycopene β-cyclase (LCYB). Previously, we demonstrated that the introduction of the Daucus carota (carrot) DcLCYB1 gene into tobacco (cv. Xanthi) resulted in increased levels of abscisic acid (ABA) and especially gibberellins (GAs), resulting in increased plant yield. In order to understand this phenomenon prior to exporting this genetic strategy to crops, we generated tobacco (Nicotiana tabacum cv. Petit Havana) mutants that exhibited a wide range of LCYB expression. Transplastomic plants expressing DcLCYB1 at high levels showed a wild-type-like growth, even though their pigment content was increased and their leaf GA1 content was reduced. RNA interference (RNAi) NtLCYB lines showed different reductions in NtLCYB transcript abundance, correlating with reduced pigment content and plant variegation. Photosynthesis (leaf absorptance, Fv/Fm, and light-saturated capacity of linear electron transport) and plant growth were impaired. Remarkably, drastic changes in phytohormone content also occurred in the RNAi lines. However, external application of phytohormones was not sufficient to rescue these phenotypes, suggesting that altered photosynthetic efficiency might be another important factor explaining their reduced biomass. These results show that LCYB expression influences plant biomass by different mechanisms and suggests thresholds for LCYB expression levels that might be beneficial or detrimental for plant growth.
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Affiliation(s)
- Stella Kössler
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Tegan Armarego-Marriott
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Danuše Tarkowská
- Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences and Palacký University, Šlechtitelů, Olomouc, Czech Republic
| | - Veronika Turečková
- Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences and Palacký University, Šlechtitelů, Olomouc, Czech Republic
| | - Shreya Agrawal
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Jianing Mi
- Center for Desert Agriculture, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Leonardo Perez de Souza
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Mark Aurel Schöttler
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Anne Schadach
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Anja Fröhlich
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Ralph Bock
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Salim Al-Babili
- Center for Desert Agriculture, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Stephanie Ruf
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Arun Sampathkumar
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
| | - Juan C Moreno
- Max Planck Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg1 D-14476, Potsdam-Golm, Germany
- Center for Desert Agriculture, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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Moreno JC, Martinez-Jaime S, Kosmacz M, Sokolowska EM, Schulz P, Fischer A, Luzarowska U, Havaux M, Skirycz A. A Multi-OMICs Approach Sheds Light on the Higher Yield Phenotype and Enhanced Abiotic Stress Tolerance in Tobacco Lines Expressing the Carrot lycopene β -cyclase1 Gene. Front Plant Sci 2021; 12:624365. [PMID: 33613605 PMCID: PMC7893089 DOI: 10.3389/fpls.2021.624365] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/18/2021] [Indexed: 05/17/2023]
Abstract
Recently, we published a set of tobacco lines expressing the Daucus carota (carrot) DcLCYB1 gene with accelerated development, increased carotenoid content, photosynthetic efficiency, and yield. Because of this development, DcLCYB1 expression might be of general interest in crop species as a strategy to accelerate development and increase biomass production under field conditions. However, to follow this path, a better understanding of the molecular basis of this phenotype is essential. Here, we combine OMICs (RNAseq, proteomics, and metabolomics) approaches to advance our understanding of the broader effect of LCYB expression on the tobacco transcriptome and metabolism. Upon DcLCYB1 expression, the tobacco transcriptome (~2,000 genes), proteome (~700 proteins), and metabolome (26 metabolites) showed a high number of changes in the genes involved in metabolic processes related to cell wall, lipids, glycolysis, and secondary metabolism. Gene and protein networks revealed clusters of interacting genes and proteins mainly involved in ribosome and RNA metabolism and translation. In addition, abiotic stress-related genes and proteins were mainly upregulated in the transgenic lines. This was well in line with an enhanced stress (high light, salt, and H2O2) tolerance response in all the transgenic lines compared with the wild type. Altogether, our results show an extended and coordinated response beyond the chloroplast (nucleus and cytosol) at the transcriptome, proteome, and metabolome levels, supporting enhanced plant growth under normal and stress conditions. This final evidence completes the set of benefits conferred by the expression of the DcLCYB1 gene, making it a very promising bioengineering tool to generate super crops.
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Affiliation(s)
- Juan C. Moreno
- Max Planck Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
- Biological and Environmental Science and Engineering Division, Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- *Correspondence: Juan C. Moreno
| | | | - Monika Kosmacz
- Max Planck Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
- Biological and Environmental Science and Engineering Division, Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Philipp Schulz
- Max Planck Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Axel Fischer
- Max Planck Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Urszula Luzarowska
- Max Planck Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
| | - Michel Havaux
- Aix-Marseille Univ., CEA, CNRS UMR7265, BIAM, CEA/Cadarache, Saint-Paul-lez-Durance, France
| | - Aleksandra Skirycz
- Max Planck Institut für Molekulare Pflanzenphysiologie, Potsdam, Germany
- Boyce Thompson Institute, Cornell University, Ithaca, NY, United States
- Aleksandra Skirycz
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Moreno JC, Cerda A, Simpson K, Lopez-Diaz I, Carrera E, Handford M, Stange C. Increased Nicotiana tabacum fitness through positive regulation of carotenoid, gibberellin and chlorophyll pathways promoted by Daucus carota lycopene β-cyclase (Dclcyb1) expression. J Exp Bot 2016; 67:2325-38. [PMID: 26893492 PMCID: PMC4809289 DOI: 10.1093/jxb/erw037] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Carotenoids, chlorophylls and gibberellins are derived from the common precursor geranylgeranyl diphosphate (GGPP). One of the enzymes in carotenoid biosynthesis is lycopene β-cyclase (LCYB) that catalyzes the conversion of lycopene into β-carotene. In carrot, Dclcyb1 is essential for carotenoid synthesis in the whole plant. Here we show that when expressed in tobacco, increments in total carotenoids, β-carotene and chlorophyll levels occur. Furthermore, photosynthetic efficiency is enhanced in transgenic lines. Interestingly, and contrary to previous observations where overexpression of a carotenogenic gene resulted in the inhibition of the synthesis of gibberellins, we found raised levels of active GA4 and the concommitant increases in plant height, leaf size and whole plant biomass, as well as an early flowering phenotype. Moreover, a significant increase in the expression of the key carotenogenic genes, Ntpsy1, Ntpsy2 and Ntlcyb, as well as those involved in the synthesis of chlorophyll (Ntchl), gibberellin (Ntga20ox, Ntcps and Ntks) and isoprenoid precursors (Ntdxs2 and Ntggpps) was observed. These results indicate that the expression of Dclcyb1 induces a positive feedback affecting the expression of isoprenoid gene precursors and genes involved in carotenoid, gibberellin and chlorophyll pathways leading to an enhancement in fitness measured as biomass, photosynthetic efficiency and carotenoid/chlorophyll composition.
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Affiliation(s)
- J C Moreno
- Centro de Biología Molecular Vegetal, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653 Ñuñoa, Santiago, Chile Current address: Max Planck Institut für Molekulare Pflanzenphysiologie, Potsdam-Golm, Germany
| | - A Cerda
- Centro de Biología Molecular Vegetal, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653 Ñuñoa, Santiago, Chile
| | - K Simpson
- Centro de Biología Molecular Vegetal, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653 Ñuñoa, Santiago, Chile
| | - I Lopez-Diaz
- Instituto de Biología Molecular y Celular de Plantas, C.S.I.C., Universidad Politécnica de Valencia, Ingeniero Fausto Elío s/n, 46022 Valencia, Spain
| | - E Carrera
- Instituto de Biología Molecular y Celular de Plantas, C.S.I.C., Universidad Politécnica de Valencia, Ingeniero Fausto Elío s/n, 46022 Valencia, Spain
| | - M Handford
- Centro de Biología Molecular Vegetal, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653 Ñuñoa, Santiago, Chile
| | - C Stange
- Centro de Biología Molecular Vegetal, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653 Ñuñoa, Santiago, Chile
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Lu S, Zhang Y, Zheng X, Zhu K, Xu Q, Deng X. Isolation and Functional Characterization of a Lycopene β-cyclase Gene Promoter from Citrus. Front Plant Sci 2016; 7:1367. [PMID: 27679644 PMCID: PMC5020073 DOI: 10.3389/fpls.2016.01367] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Accepted: 08/29/2016] [Indexed: 05/19/2023]
Abstract
Lycopene β-cyclases are key enzymes located at the branch point of the carotenoid biosynthesis pathway. However, the transcriptional regulatory mechanisms of LCYb1 in citrus with abundant carotenoid accumulation are still unclear. To understand the molecular basis of CsLCYb1 expression, we isolated and functionally characterized the 5' upstream sequences of CsLCYb1 from citrus. The full-length CsLCYb1 promoter and a series of its 5' deletions were fused to the β-glucuronidase (GUS) reporter gene and transferred into different plants (tomato, Arabidopsis and citrus callus) to test the promoter activities. The results of all transgenic species showed that the 1584 bp upstream region from the translational start site displayed maximal promoter activity, and the minimal promoter containing 746 bp upstream sequences was sufficient for strong basal promoter activity. Furthermore, the CsLCYb1 promoter activity was developmentally and tissue-specially regulated in transgenic Arabidopsis, and it was affected by multiple hormones and environmental cues in transgenic citrus callus under various treatments. Finer deletion analysis identified an enhancer element existing as a tandem repeat in the promoter region between -574 to -513 bp and conferring strong promoter activity. The copy numbers of the enhancer element differed among various citrus species, leading to the development of a derived simple sequence repeat marker to distinguish different species. In conclusion, this study elucidates the expression characteristics of the LCYb1 promoter from citrus and further identifies a novel enhancer element required for the promoter activity. The characterized promoter fragment would be an ideal candidate for genetic engineering and seeking of upstream trans-acting elements.
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Shi Y, Guo J, Zhang W, Jin L, Liu P, Chen X, Li F, Wei P, Li Z, Li W, Wei C, Zheng Q, Chen Q, Zhang J, Lin F, Qu L, Snyder JH, Wang R. Cloning of the Lycopene β-cyclase Gene in Nicotiana tabacum and Its Overexpression Confers Salt and Drought Tolerance. Int J Mol Sci 2015; 16:30438-57. [PMID: 26703579 PMCID: PMC4691183 DOI: 10.3390/ijms161226243] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 12/11/2015] [Accepted: 12/15/2015] [Indexed: 12/24/2022] Open
Abstract
Carotenoids are important pigments in plants that play crucial roles in plant growth and in plant responses to environmental stress. Lycopene β cyclase (β-LCY) functions at the branch point of the carotenoid biosynthesis pathway, catalyzing the cyclization of lycopene. Here, a β-LCY gene from Nicotiana tabacum, designated as Ntβ-LCY1, was cloned and functionally characterized. Robust expression of Ntβ-LCY1 was found in leaves, and Ntβ-LCY1 expression was obviously induced by salt, drought, and exogenous abscisic acid treatments. Strong accumulation of carotenoids and expression of carotenoid biosynthesis genes resulted from Ntβ-LCY1 overexpression. Additionally, compared to wild-type plants, transgenic plants with overexpression showed enhanced tolerance to salt and drought stress with higher abscisic acid levels and lower levels of malondialdehyde and reactive oxygen species. Conversely, transgenic RNA interference plants had a clear albino phenotype in leaves, and some plants did not survive beyond the early developmental stages. The suppression of Ntβ-LCY1 expression led to lower expression levels of genes in the carotenoid biosynthesis pathway and to reduced accumulation of carotenoids, chlorophyll, and abscisic acid. These results indicate that Ntβ-LCY1 is not only a likely cyclization enzyme involved in carotenoid accumulation but also confers salt and drought stress tolerance in Nicotiana tabacum.
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Affiliation(s)
- Yanmei Shi
- College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China.
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Jinggong Guo
- Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, Henan, China.
| | - Wei Zhang
- China National Tobacco Quality Supervision & Test Centre, Zhengzhou 450001, Henan, China.
| | - Lifeng Jin
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Pingping Liu
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Xia Chen
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Feng Li
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Pan Wei
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Zefeng Li
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Wenzheng Li
- Yunnan Academy of Tobacco Agricultural Sciences, Kunming 650031, Yunnan, China.
| | - Chunyang Wei
- Staff Training Academy of CNTC, Zhengzhou 450008, Henan, China.
| | - Qingxia Zheng
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Qiansi Chen
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Jianfeng Zhang
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Fucheng Lin
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Lingbo Qu
- College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, Henan, China.
| | - John Hugh Snyder
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
| | - Ran Wang
- National Tobacco Gene Research Center, Zhengzhou Tobacco Research Institute, Zhengzhou 450001, Henan, China.
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Zeng J, Wang C, Chen X, Zang M, Yuan C, Wang X, Wang Q, Li M, Li X, Chen L, Li K, Chang J, Wang Y, Yang G, He G. The lycopene β-cyclase plays a significant role in provitamin A biosynthesis in wheat endosperm. BMC Plant Biol 2015; 15:112. [PMID: 25943989 PMCID: PMC4433027 DOI: 10.1186/s12870-015-0514-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 04/29/2015] [Indexed: 05/04/2023]
Abstract
BACKGROUND Lycopene β-cyclase (LCYB) is a key enzyme catalyzing the biosynthesis of β-carotene, the main source of provitamin A. However, there is no documented research about this key cyclase gene's function and relationship with β-carotene content in wheat. Therefore, the objectives of this study were to clone TaLCYB and characterize its function and relationship with β-carotene biosynthesis in wheat grains. We also aimed to obtain more information about the endogenous carotenoid biosynthetic pathway and thus provide experimental support for carotenoid metabolic engineering in wheat. RESULTS In the present study, a lycopene β-cyclase gene, designated TaLCYB, was cloned from the hexaploid wheat cultivar Chinese Spring. The cyclization activity of the encoded protein was demonstrated by heterologous complementation analysis. The TaLCYB gene was expressed differentially in different tissues of wheat. Although TaLCYB had a higher expression level in the later stages of grain development, the β-carotene content still showed a decreasing tendency. The expression of TaLCYB in leaves was dramatically induced by strong light and the β-carotene content variation corresponded with changes of TaLCYB expression. A post-transcriptional gene silencing strategy was used to down-regulate the expression of TaLCYB in transgenic wheat, resulting in a decrease in the content of β-carotene and lutein, accompanied by the accumulation of lycopene to partly compensate for the total carotenoid content. In addition, changes in TaLCYB expression also affected the expression of several endogenous carotenogenic genes to varying degrees. CONCLUSION Our results suggest that TaLCYB is a genuine lycopene cyclase gene and plays a crucial role in β-carotene biosynthesis in wheat. Our attempt to silence it not only contributes to elucidating the mechanism of carotenoid accumulation in wheat but may also help in breeding wheat varieties with high provitamin A content through RNA interference (RNAi) to block specific carotenogenic genes in the wheat endosperm.
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Affiliation(s)
- Jian Zeng
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Cheng Wang
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Xi Chen
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Mingli Zang
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Cuihong Yuan
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Xiatian Wang
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Qiong Wang
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Miao Li
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Xiaoyan Li
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Ling Chen
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Kexiu Li
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Junli Chang
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Yuesheng Wang
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Guangxiao Yang
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
| | - Guangyuan He
- The Genetic Engineering International Cooperation Base of Chinese Ministry of Science and Technology, The Key Laboratory of Molecular Biophysics of Chinese Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
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Kim SH, Ahn YO, Ahn MJ, Jeong JC, Lee HS, Kwak SS. Cloning and characterization of an Orange gene that increases carotenoid accumulation and salt stress tolerance in transgenic sweetpotato cultures. Plant Physiol Biochem 2013; 70:445-54. [PMID: 23835362 DOI: 10.1016/j.plaphy.2013.06.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 06/13/2013] [Indexed: 05/19/2023]
Abstract
The Orange (Or) gene is responsible for the accumulation of carotenoids in plants. We isolated the Or gene (IbOr) from storage roots of orange-fleshed sweetpotato (Ipomoea batatas L. Lam. cv. Sinhwangmi), and analyzed its function in transgenic sweetpotato calli. The IbOr gene has an open reading frame in the 942 bp cDNA, which encodes a 313-amino acid protein containing a cysteine-rich zinc finger domain. IbOr was strongly expressed in storage roots of orange-fleshed sweetpotato cultivars; it also was expressed in leaves, stems, and roots of cultivars with alternatively colored storage roots. IbOr transcription increased in response to abiotic stress, with gene expression reaching maximum at 2 h after treatment. Two different overexpression vectors of IbOr (IbOr-Wt and IbOr-Ins, which contained seven extra amino acids) were transformed into calli of white-fleshed sweetpotato [cv. Yulmi (Ym)] using Agrobacterium. The transgenic calli were easily selected because they developed a fine orange color. The expression levels of the IbOr transgene and genes involved in carotenoid biosynthesis in IbOr-Wt and IbOr-Ins transgenic calli were similar, and both transformants displayed higher expression levels than those in Ym calli. The contents of β-carotene, lutein, and total carotenoids in IbOr-Ins transgenic lines were approximately 10, 6, and 14 times higher than those in Ym calli, respectively. The transgenic IbOr calli exhibited increased antioxidant activity and increased tolerance to salt stress. Our work shows that the IbOr gene may be useful for the biotechnological development of transgenic sweetpotato plants that accumulate increased carotenoid contents on marginal agricultural lands.
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Affiliation(s)
- Sun Ha Kim
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806, Republic of Korea
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10
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Domonkos I, Kis M, Gombos Z, Ughy B. Carotenoids, versatile components of oxygenic photosynthesis. Prog Lipid Res 2013; 52:539-61. [PMID: 23896007 DOI: 10.1016/j.plipres.2013.07.001] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/19/2013] [Accepted: 07/19/2013] [Indexed: 12/13/2022]
Abstract
Carotenoids (CARs) are a group of pigments that perform several important physiological functions in all kingdoms of living organisms. CARs serve as protective agents, which are essential structural components of photosynthetic complexes and membranes, and they play an important role in the light harvesting mechanism of photosynthesizing plants and cyanobacteria. The protection against reactive oxygen species, realized by quenching of singlet oxygen and the excited states of photosensitizing molecules, as well as by the scavenging of free radicals, is one of the main biological functions of CARs. X-ray crystallographic localization of CARs revealed that they are present at functionally and structurally important sites of both the PSI and PSII reaction centers. Characterization of a CAR-less cyanobacterial mutant revealed that while the absence of CARs prevents the formation of PSII complexes, it does not abolish the assembly and function of PSI. CAR molecules assist in the formation of protein subunits of the photosynthetic complexes by gluing together their protein components. In addition to their aforementioned indispensable functions, CARs have a substantial role in the formation and maintenance of proper cellular architecture, and potentially also in the protection of the translational machinery under stress conditions.
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Affiliation(s)
- Ildikó Domonkos
- Institute of Plant Biology, Biological Research Centre of Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged, Hungary
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Tuan PA, Thwe AA, Kim JK, Kim YB, Lee S, Park SU. Molecular characterisation and the light-dark regulation of carotenoid biosynthesis in sprouts of tartary buckwheat (Fagopyrum tataricum Gaertn.). Food Chem 2013; 141:3803-12. [PMID: 23993552 DOI: 10.1016/j.foodchem.2013.06.085] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 06/13/2013] [Accepted: 06/18/2013] [Indexed: 12/15/2022]
Abstract
Seven partial-length cDNAs and 1 full-length cDNA that were involved in carotenoid biosynthesis and 2 partial-length cDNAs that encoded carotenoid cleavage dioxygenases were first isolated and characterised in 2 tartary buckwheat cultivars (Fagopyrum tataricum Gaertn.), Hokkai T8 and Hokkai T10. They were constitutively expressed at high levels in the leaves and flowers, where carotenoids are mostly distributed. During the seed development of tartary buckwheat, an inverse correlation between transcription level of carotenoid cleavage dioxygenase and carotenoid content was observed. The light-grown sprouts exhibited higher levels of expression of carotenoid biosynthetic genes in T10 and carotenoid content in both T8 and T10 compared to the dark-grown sprouts. The predominant carotenoids in tartary buckwheat were lutein and β-carotene, and very abundant amounts of these carotenoids were found in light-grown sprouts. This study might broaden our understanding of the molecular mechanisms involved in carotenoid biosynthesis and indicates targets for increasing the production of carotenoids in tartary buckwheat.
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Affiliation(s)
- Pham Anh Tuan
- Department of Crop Science, Chungnam National University, 99 Daehak-ro, Yuseong-Gu, Daejeon 305-764, South Korea
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12
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Jeknić Z, Morré JT, Jeknić S, Jevremović S, Subotić A, Chen TH. Cloning and functional characterization of a gene for capsanthin-capsorubin synthase from tiger lily (Lilium lancifolium Thunb. 'Splendens'). Plant Cell Physiol 2012; 53:1899-912. [PMID: 23008421 PMCID: PMC3494009 DOI: 10.1093/pcp/pcs128] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 09/17/2012] [Indexed: 05/19/2023]
Abstract
The orange color of tiger lily (Lolium lancifolium 'Splendens') flowers is due, primarily, to the accumulation of two κ-xanthophylls, capsanthin and capsorubin. An enzyme, known as capsanthin-capsorubin synthase (CCS), catalyzes the conversion of antheraxanthin and violaxanthin into capsanthin and capsorubin, respectively. We cloned the gene for capsanthin-capsorubin synthase (Llccs) from flower tepals of L. lancifolium by the rapid amplification of cDNA ends (RACE) with a heterologous non-degenerate primer that was based on the sequence of a gene for lycopene β-cyclase (lcyB). The full-length cDNA of Llccs was 1,785 bp long and contained an open reading frame of 1,425 bp that encoded a polypeptide of 474 amino acids with a predicted N-terminal plastid-targeting sequence. Analysis by reverse transcription-PCR (RT-PCR) revealed that expression of Llccs was spatially and temporally regulated, with expression in flower buds and flowers of L. lancifolium but not in vegetative tissues. Stable overexpression of the Llccs gene in callus tissue of Iris germanica, which accumulates several xanthophylls including violaxanthin, the precursor of capsorubin, resulted in transgenic callus whose color had changed from its normal yellow to red-orange. This novel red-orange coloration was due to the accumulation of two non-native κ-xanthophylls, capsanthin and capsorubin, as confirmed by HPLC and ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis with authentic standards. Cloning of the Llccs gene should advance our understanding of the molecular and genetic mechanisms of the biosynthesis of κ-carotenoids in general and in the genus Lilium in particular, and will facilitate transgenic alterations of the colors of flowers and fruits of many plant species.
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MESH Headings
- Amino Acid Sequence
- Chromatography, High Pressure Liquid
- Cloning, Molecular
- Color
- DNA, Complementary/genetics
- DNA, Complementary/metabolism
- Flowers/enzymology
- Flowers/genetics
- Gene Expression Regulation, Enzymologic
- Gene Expression Regulation, Plant
- Genes, Plant
- Intramolecular Lyases/genetics
- Intramolecular Lyases/metabolism
- Iris Plant/genetics
- Iris Plant/metabolism
- Lilium/enzymology
- Lilium/genetics
- Molecular Sequence Data
- Open Reading Frames
- Oxidoreductases/genetics
- Oxidoreductases/metabolism
- Phylogeny
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Plants, Genetically Modified/enzymology
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Tandem Mass Spectrometry/methods
- Xanthophylls/biosynthesis
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Affiliation(s)
- Zoran Jeknić
- Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
| | - Jeffrey T. Morré
- Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA
| | - Stevan Jeknić
- Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
| | - Slađana Jevremović
- Institute for Biological Research ‘Siniša Stanković’, University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Angelina Subotić
- Institute for Biological Research ‘Siniša Stanković’, University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade, Serbia
| | - Tony H.H. Chen
- Department of Horticulture, Oregon State University, Corvallis, OR 97331, USA
- *Corresponding author: E-mail, ; Fax, +1-541-737-3479.
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Devitt LC, Fanning K, Dietzgen RG, Holton TA. Isolation and functional characterization of a lycopene beta-cyclase gene that controls fruit colour of papaya (Carica papaya L.). J Exp Bot 2010; 61:33-9. [PMID: 19887502 PMCID: PMC2791114 DOI: 10.1093/jxb/erp284] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 08/04/2009] [Accepted: 08/04/2009] [Indexed: 05/19/2023]
Abstract
The colour of papaya fruit flesh is determined largely by the presence of carotenoid pigments. Red-fleshed papaya fruit contain lycopene, whilst this pigment is absent from yellow-fleshed fruit. The conversion of lycopene (red) to beta-carotene (yellow) is catalysed by lycopene beta-cyclase. This present study describes the cloning and functional characterization of two different genes encoding lycopene beta-cyclases (lcy-beta1 and lcy-beta2) from red (Tainung) and yellow (Hybrid 1B) papaya cultivars. A mutation in the lcy-beta2 gene, which inactivates enzyme activity, controls lycopene production in fruit and is responsible for the difference in carotenoid production between red and yellow-fleshed papaya fruit. The expression level of both lcy-beta1 and lcy-beta2 genes is similar and low in leaves, but lcy-beta2 expression increases markedly in ripe fruit. Isolation of the lcy-beta2 gene from papaya, that is preferentially expressed in fruit and is correlated with fruit colour, will facilitate marker-assisted breeding for fruit colour in papaya and should create possibilities for metabolic engineering of carotenoid production in papaya fruit to alter both colour and nutritional properties.
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Affiliation(s)
- Luke C. Devitt
- Department of Employment, Economic Development and Innovation (DEEDI), Primary Industries and Fisheries, Queensland Agricultural Biotechnology Centre, PO Box 6097, Australia
- The University of Queensland, School of Chemistry and Molecular Biosciences, St Lucia QLD 4067, Australia
| | - Kent Fanning
- DEEDI, Primary Industries and Fisheries, Innovative Food Technologies, Hamilton QLD 4007, Australia
| | - Ralf G. Dietzgen
- Department of Employment, Economic Development and Innovation (DEEDI), Primary Industries and Fisheries, Queensland Agricultural Biotechnology Centre, PO Box 6097, Australia
- The University of Queensland, School of Chemistry and Molecular Biosciences, St Lucia QLD 4067, Australia
| | - Timothy A. Holton
- Department of Employment, Economic Development and Innovation (DEEDI), Primary Industries and Fisheries, Queensland Agricultural Biotechnology Centre, PO Box 6097, Australia
- To whom correspondence should be addressed: E-mail:
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Alquézar B, Zacarías L, Rodrigo MJ. Molecular and functional characterization of a novel chromoplast-specific lycopene beta-cyclase from Citrus and its relation to lycopene accumulation. J Exp Bot 2009; 60:1783-97. [PMID: 19325166 PMCID: PMC2671624 DOI: 10.1093/jxb/erp048] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 02/04/2009] [Accepted: 02/05/2009] [Indexed: 05/19/2023]
Abstract
Carotenoids are the main pigments responsible of the colouration of Citrus fruits. The beta-cyclization of lycopene, catalysed by the lycopene beta-cyclases (beta-LCY), seems to be a key regulatory step of the carotenoid pathway. In the present study, two beta-LCYs from orange fruits (Citrus sinensis), named Csbeta-LCY1 and Csbeta-LCY2 have been isolated and the activity of the encoded proteins was demonstrated by functional analysis. Csbeta-LCY1 was expressed at low levels and remained relatively constant during fruit ripening while Csbeta-LCY2 showed a chromoplast-specific expression and a marked induction in both peel and pulp of orange fruits in parallel with the accumulation of beta,beta-xanthophylls. The potential involvement of Csbeta-LCY2 in the accumulation of lycopene, characteristic of some Citrus species such as red grapefruits, was investigated. Expression of Csbeta-LCY2 and another seven carotenoid biosynthetic genes were studied in the peel and pulp of the high lycopene-accumulating grapefruit, Star Ruby, and compared with those of ordinary Navel orange. In Star Ruby, the accumulation of lycopene during fruit maturation was associated with a substantial reduction in the expression of both beta-LCY2 and beta-CHX genes with respect to Navel orange. Moreover, two different alleles of beta-LCY2: beta-LCY2a and beta-LCY2b were isolated from both genotypes, and functional assays demonstrated that the lycopene beta-cyclase activity of the allele b was almost null. Interestingly, Star Ruby grapefruit predominantly expressed the unfunctional beta-LCY2b allele during fruit ripening whereas Navel oranges preferably expressed the functional allele. It is suggested that the presence of diverse alleles of the beta-LCY2 gene, encoding enzymes with altered activity, with different transcript accumulation may be an additional regulatory mechanism of carotenoid synthesis involved in the accumulation of lycopene in red grapefruits.
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Aluru M, Xu Y, Guo R, Wang Z, Li S, White W, Wang K, Rodermel S. Generation of transgenic maize with enhanced provitamin A content. J Exp Bot 2008; 59:3551-62. [PMID: 18723758 PMCID: PMC2561147 DOI: 10.1093/jxb/ern212] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 07/15/2008] [Accepted: 07/15/2008] [Indexed: 05/19/2023]
Abstract
Vitamin A deficiency (VAD) affects over 250 million people worldwide and is one of the most prevalent nutritional deficiencies in developing countries, resulting in significant socio-economic losses. Provitamin A carotenoids such as beta-carotene, are derived from plant foods and are a major source of vitamin A for the majority of the world's population. Several years of intense research has resulted in the production of 'Golden Rice 2' which contains sufficiently high levels of provitamin A carotenoids to combat VAD. In this report, the focus is on the generation of transgenic maize with enhanced provitamin A content in their kernels. Overexpression of the bacterial genes crtB (for phytoene synthase) and crtI (for the four desaturation steps of the carotenoid pathway catalysed by phytoene desaturase and zeta-carotene desaturase in plants), under the control of a 'super gamma-zein promoter' for endosperm-specific expression, resulted in an increase of total carotenoids of up to 34-fold with a preferential accumulation of beta-carotene in the maize endosperm. The levels attained approach those estimated to have a significant impact on the nutritional status of target populations in developing countries. The high beta-carotene trait was found to be reproducible over at least four generations. Gene expression analyses suggest that increased accumulation of beta-carotene is due to an up-regulation of the endogenous lycopene beta-cylase. These experiments set the stage for the design of transgenic approaches to generate provitamin A-rich maize that will help alleviate VAD.
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Affiliation(s)
- Maneesha Aluru
- Department of Genetics, Development and Cell Biology, 253 Bessey Hall, Iowa State University, Ames, IA 50011, USA
| | - Yang Xu
- Department of Genetics, Development and Cell Biology, 253 Bessey Hall, Iowa State University, Ames, IA 50011, USA
| | - Rong Guo
- Department of Genetics, Development and Cell Biology, 253 Bessey Hall, Iowa State University, Ames, IA 50011, USA
| | - Zhenguo Wang
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Shanshan Li
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Wendy White
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011, USA
| | - Kan Wang
- Department of Agronomy, Iowa State University, Ames, IA 50011, USA
| | - Steve Rodermel
- Department of Genetics, Development and Cell Biology, 253 Bessey Hall, Iowa State University, Ames, IA 50011, USA
- To whom correspondence should be addressed: E-mail:
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